Milk mineral concentration is important from both the perspective of processing milk into dairy products and its nutritive value for human consumption. Precise estimates of genetic parameters for milk mineral concentration are lacking because of the considerable resources required to collect vast phenotypes quantities. The milk concentration of calcium (Ca), potassium (K), magnesium (Mg), sodium (Na) and phosphorus (P) in the present study was quantified from mid-IR spectroscopy on 12 223 test-day records from 1717 Holstein-Friesian cows. (Co)variance components were estimated using random regressions to model both the additive genetic and within-lactation permanent environmental variances of each trait. The coefficient of genetic variation averaged across days-in-milk (DIM) was 6.93%, 3.46%, 6.55%, 5.20% and 6.68% for Ca, K, Mg, Na and P concentration, respectively; heritability estimates varied across lactation from 0.31±0.05 (5 DIM) to 0.67±0.04 (181 DIM) for Ca, from 0.18±0.03 (60 DIM) to 0.24±0.05 (305 DIM) for K, from 0.08±0.03 (15 DIM) to 0.37±0.03 (223 DIM) for Mg, from 0.16±0.03 (30 DIM) to 0.37±0.04 (305 DIM) for Na and from 0.21±0.04 (12 DIM) to 0.57±0.04 (211 DIM) for P. Genetic correlations within the same trait across different DIM were almost unity between adjacent DIM but weakened as the time interval between pairwise compared DIM lengthened; genetic correlations were weaker than 0.80 only when comparing both peripheries of the lactation. The analysis of the geometry of the additive genetic covariance matrix revealed that almost 90% of the additive genetic variation was accounted by the intercept term of the covariance functions for each trait. Milk protein concentration and mineral concentration were, in general, positively genetically correlated with each other across DIM, whereas milk fat concentration was positively genetically correlated throughout the entire lactation with Ca, K and Mg; the genetic correlation with fat concentration changed from negative to positive with Na and P at 243 DIM and 50 DIM, respectively. Genetic correlations between somatic cell score and Na ranged from 0.38±0.21 (5 DIM) to 0.79±0.18 (305 DIM). Exploitable genetic variation existed for all milk minerals, although many national breeding objectives are probably contributing to an indirect positive response to selection in milk mineral concentration.

Circular data originates in a wide range of scientific fields and can be analyzed on the basis of directional statistics and special distributions wrapped around the circumference. However, both propensity to transform non-linear to linear data and complexity of directional statistics limited the generalization of the circular paradigm in the animal breeding framework, among others. Here, we generalized a circular mixed (CM) model within the context of Bayesian inference. Three different parametrizations with different hierarchical structures were developed on basis of the von Mises distribution; moreover, both goodness of fit and predictive ability from each parametrization were compared through the analyses of 110 116 lambing distribution records collected from Ripollesa sheep herds between 1976 and 2017. The naive circular (NC) model only accounted for population mean and homogeneous circular variance, and reached the lowest goodness-of-fit and predictive ability. The CM model assumed a hierarchical structure for the population mean by accounting for systematic (ewe age and lambing interval) and permanent environmental sources of variation (flock-year-season and ewe). This improved goodness of fit by reducing both the deviance information criterion (DIC; −2520 units) and the mean square error (MSE; −12.4%) between simulated and predicted lambing data when compared against the NC model. Finally, the last parametrization expanded CM model by also assuming a hierarchical structure with systematic and permanent environmental factors for the variance parameter of the von Mises distribution (i.e. circular canalization (CC) model). This last model reached the best goodness of fit to lambing distribution data with a DIC estimate 5425 units lower than the one for NC model (MSE reduced 13.2%). The same pattern revealed when models were compared in terms of predictive ability. The superiority revealed by CC model emphasized the relevance of heteroskedasticity for the analysis of lambing distribution in the Ripollesa breed, and suggested potential applications for the sheep industry, even genetic selection for canalization. The development of CM models on the basis of the von Mises distribution has allowed to integrate flexible hierarchical structures accounting for different sources of variation and affecting both mean and dispersion terms. This must be viewed as a useful statistical tool with multiple applications in a wide range of research fields, as well as the livestock industry. The next mandatory step should be the inclusion of genetic terms in the hierarchical structure of the models in order to evaluate their potential contribution to current selection programs.

Subcutaneous fat thickness and fatty acid composition (FAC) play an important role on seasoning loss and organoleptic characteristics of seasoned hams. Dry-cured ham industry prefers meats with low contents of polyunsaturated fatty acids (PUFA) because these negatively affect fat firmness and ham quality, whereas consumers require higher contents in those fatty acids (FA) for their positive effect on human health. A population of 950 Italian Large White pigs from the Italian National Sib Test Selection Programme was investigated with the aim to estimate heritabilities, genetic and phenotypic correlations of backfat FAC, Semimembranosus muscle intramuscular fat (IMF) content and other carcass traits. The pigs were reared in controlled environmental condition at the same central testing station and were slaughtered at reaching 150 kg live weight. Backfat samples were collected to analyze FAC by gas chromatography. Carcass traits showed heritability levels from 0.087 for estimated carcass lean percentage to 0.361 for hot carcass weight. Heritability values of FA classes were low-to-moderate, all in the range 0.245 for n-3 PUFA to 0.264 for monounsaturated FA (MUFA). Polyunsaturated fatty acids showed a significant genetic correlation with loin thickness (0.128), backfat thickness (−0.124 for backfat measured by Fat-O-Meat’er and −0.175 for backfat measured by calibre) and IMF (−0.102). Obviously, C18:2(n-6) shows similar genetic correlations with the same traits (0.211 with loin thickness, −0.206 with backfat measured by Fat-O-Meat’er, −0.291 with backfat measured by calibre and −0.171 with IMF). Monounsaturated FA, except with the backfat measured by calibre (0.068; P<0.01), do not show genetic correlations with carcass characteristics, whereas a negative genetic correlation was found between MUFA and saturated FA (SFA; −0.339; P<0.001). These results suggest that MUFA/SFA ratio could be increased without interfering with carcass traits. The level of genetic correlations between FA and carcass traits should be taken into account in dealing with the development of selection schemes addressed to modify carcass composition and/or backfat FAC.

l-theanine is a unique nonproteinogenic amino acid found in tea, and has recently received considerable attention because of its various biological activities. However, there is no available research report on the use of l-theanine as a feed additive in ducks. This study was conducted to investigate the potential benefits and appropriate dosages of l-theanine on the growth performance, immune function, serum biochemical parameters, and jejunum morphology and antioxidant capacity of ducks. A total of 600 1-day-old Chaohu ducks were randomly allocated into five dietary treatment groups supplemented with 0 (control group), 300, 600, 900 and 1500 mg/kg of l-theanine. Each group included five replicates of 24 birds each. Body weight at day 28 was increased (P<0.05) by l-theanine. From days 15 to 28, l-theanine elevated cumulative BW gain (BWG) and cumulative feed intake (FI), and decreased feed to gain ratio. From days 1 to 28, l-theanine elevated (P<0.05) cumulative BWG and cumulative FI. l-theanine elevated (P<0.05) the relative weight of bursa of Fabricus (day 14), thymus (day 14), spleen (day 28) and liver (day 28). On day 28, l-theanine decreased (P<0.05) serum glucose, uric acid, triacylglycerol, total cholesterol, low-density lipoprotein cholesterol, insulin, interleukin-2 (IL-2) and IL-6 contents, and elevated (P<0.05) serum total protein, globulin (GLB), immune globulin A (IgA) and IgG contents, but only serum insulin, interferon-γ, tumor necrosis factor-α and IL-6 contents was decreased (P<0.05) and serum GLB and IgM content was elevated (P<0.05) by l-theanine on day 14. On day 14, l-theanine decreased (P<0.05) jejunum crypt depth, and elevated (P<0.05) jejunum villus height, villus height to crypt depth ratio (V/C), goblet cell number and total superoxide dismutase (T-SOD) activity. On day 28, l-theanine decreased (P<0.05) jejunum malondialdehyde content, and elevated (P<0.05) jejunum villus height, V/C, goblet cell number, and T-SOD, catalase and glutathione peroxidase activities. l-theanine levels caused quadratic effect on the growth performance, relative organ weight, serum parameters, jejunum morphology and antioxidant capacity. In conclusion, l-theanine can be used as a promising feed additive for ducks, and its optimal supplementation level was 600 to 900 mg/kg based on the current experimental condition.

Soybean meal in broiler chicken diets can partly be replaced by faba bean seeds. Unfortunately, high levels of antinutritional factors and resistant starch found in these seeds can have a detrimental impact on both broiler chickens’ performance and nutrient digestibility. It is, however, possible to increase the usefulness of faba bean for broiler nutrition by a technological process known as extrusion. In this study, the authors made and attempt to investigate the effect of different forms of faba bean seeds (raw or extruded) on broiler chicken performance, nitrogen-corrected apparent metabolizable energy values (AMEN), nutrient utilization and meat quality, as well as on the excretion of total and free sialic acids. In the trial, the total of 160 1-day-old male broiler chicks of the Ross 308 strain were used. Experimental birds were randomly assigned to two dietary treatments, each containing 10 replication (floor pens); one replication included nine birds. The first group contained 300 g/kg diet of raw faba bean seeds, whereas the second group – 300 g/kg diet of extruded faba bean seeds. The applied extrusion process was found to exert a positive impact and led to a decrease in phytic phosphorus, H, NDF, ADF and resistant starch content in studied faba bean seeds. Experimental birds fed diets containing extruded faba bean seeds were characterized by a lower feed intake (2299 g) and feed conversion ratios (FCRs) (1.52 g/g) in comparison with the other group (feed intake 2466 g; FCR 1.61 g/g). Extrusion of faba bean seeds improved dry matter retention, dietary AMEN value, apparent ileal digestibility of dry matter and starch, as well as most amino acids. In addition, the above-mentioned process resulted in a decrease in the excretion of total and free sialic acids. Extruded faba bean seeds failed to have a significant impact on broiler meat quality. It was concluded that application of extrusion can increase the use of faba bean seeds in broiler chicken nutrition.

The increasing global need to find alternative protein/energy sources has triggered research in the field of non-conventional feed ingredients, with insects and former foodstuffs being the most promising. Insects contain high level of protein and fat, whereas former foodstuffs contain high energy in the form of carbohydrates and fats; therefore, both should be considered as promising alternative feed ingredients for livestock production. In addition to the nutritional value, they also represent a way by which food waste biomasses/streams can be upgraded to valuable feed ingredients. This review outlines the main nutritional and safety issues of insects and former foodstuffs, and also considers the legal framework involved. The importance of the type of insect metamorphosis and tailored substrates that could lead to the production of a premium feed is also described. This is also the first time that a review discusses the nutritional quality of former foodstuffs. Energy and the main nutrient content of former foodstuff are compared with the composition of common cereals as the principal energy sources in animal feed. For both ingredients a critical review of the safety issues is provided. Based on the current data available, both insects and former foodstuffs have an excellent potential use as alternative feed ingredients for livestock production. When produced in line with the criteria set by major feed/food authorities, they are characterized by high quality and safety standards. This makes them comparable to other feed materials and ingredients currently available on the market, although their full nutritional, functional, safety and sustainability evaluation cannot be considered complete.

Recent studies suggest that the use of vegetable oils at expense of fish oil in aquaculture feeds might have potential negative effects on fish redox homeostasis and adiposity. Resveratrol (RESV) is a lipid-soluble phytoalexin present in fruits and vegetables with proven in vivo antioxidant function in animals. The present study aims to assess the potential use of RESV in Atlantic salmon feeds. To this end, post-smolt salmons with an initial BW of 148±3 g were fed four experimental diets for 15 weeks. A diet low in fish oil served as a control and was supplemented with 0, 0.5, 1.5 and 2.5 g/kg of RESV, respectively. The effect of the experimental diets on animal performance, tissue fatty acid composition, and the expression of genes encoding proteins involved in antioxidant signalling, lipid peroxidation, and metabolism were studied. Resveratrol significantly reduced feed intake and final BW of the salmon. Feeding RESV did not affect the sum of saturated and monounsaturated fatty acids or total lipids in the fillet. While the content of total polyunsaturated fatty acids was not affected, the percentages of some fatty acids in the liver and fillet were changed by RESV. Furthermore, in liver, the relative expression of glutathione peroxidase 4b, nuclear factor-like 2, and arachidonate 5-lipoxygenase remained unchanged across treatment groups. In conclusion, the negative impact of dietary RESV on FI and hence reduction of the BW discourages its inclusion in low fish oil diets for Atlantic salmon.

In equines, Cr2O3 is widely accepted as an indigestible marker, but there are health concerns regarding the carcinogenic properties of Cr2O3. Recently, TiO2 has been suggested to be an alternative digestibility marker in equines. However, a comparison between Cr2O3 and TiO2 has not been made in equines. Six Welsh pony geldings (initial BW: 254±3 kg; 7 years of age) fed chopped alfalfa hay were used to evaluate the use of TiO2 (Ti) and Cr2O3 (Cr) as markers for calculating apparent digestibility and to investigate the effect of frequency of marker administration on the measurement of digestibility values. Diets contained 4.65 kg dry matter (DM) chopped alfalfa hay supplemented with minerals, vitamins, TiO2 (3.3 g Ti/day) and Cr2O3 (3.2 g Cr/day). Ponies were dosed with either 3.3 g Ti and 3.2 g Cr once daily (DF1) or with 1.65 g Ti and 1.60 g Cr twice daily (DF2). After adaptation to the diets and procedures for 14 days, voluntary voided faeces were collected quantitatively over 7 days and analysed for moisture, ash, Ti and Cr. Apparent total tract DM digestibility (DMD) and organic matter digestibility (OMD) were calculated using the total faecal collection (TFC) and marker method (Ti and Cr). The overall mean cumulative faecal recovery of Cr and Ti (as % of intake) were 102.0% and 96.6%, respectively. Mean daily faecal recoveries of Cr as well as of Ti were not different (P=0.323; P=0.808, respectively) between treatments. Overall daily faecal recovery of Cr differed (P=0.019) from 100% when the marker was dosed once daily, whereas overall daily faecal recovery was similar to 100% for both administration frequencies when Ti was used as a marker. For both markers, the coefficient of variation of the mean faecal marker recovery between horses was lower when the markers were administrated twice per day. Across treatments, cumulative DMD and OMD estimated with Ti were similar (P=0.345; P=0.418, respectively) compared with those values determined by TFC method. When Cr was used, the calculated cumulative DMD tended (P=0.097) to be greater compared with those estimated with TFC, and cumulative OMD values were overestimated (P=0.013). Orally supplemented Ti recovery in the faeces of ponies fed chopped alfalfa hay with Ti administered once or twice daily was close to 100%, making it the preferred marker for digestibility trials in equines.

Single-step genomic BLUP (ssGBLUP) has been widely used in genomic evaluation due to relatively higher prediction accuracy and simplicity of use. The prediction accuracy from ssGBLUP depends on the amount of information available concerning both genotype and phenotype. This study investigated how information on genotype and phenotype that had been acquired from previous generations influences the prediction accuracy of ssGBLUP, and thus we sought an optimal balance about genotypic and phenotypic information to achieve a cost-effective and computationally efficient genomic evaluation. We generated two genetically correlated traits (h2 = 0.35 for trait A, h2 = 0.10 for trait B and genetic correlation 0.20) as well as two distinct populations mimicking purebred swine. Phenotypic and genotypic information in different numbers of previous generations and different genotyping rates for each litter were set to generate different datasets. Prediction accuracy was evaluated by correlating genomic estimated breeding values with true breeding values for genotyped animals in the last generation. The results revealed a negligible impact of previous generations that lacked genotyped animals on the prediction accuracy. Phenotypic and genotypic data, including the most recent three to four generations with a genotyping rate of 40% or 50% for each litter, could lead to asymptotic maximum prediction accuracy for genotyped animals in the last generation. Single-step genomic best linear unbiased prediction yielded an optimal balance about genotypic and phenotypic information to ensure a cost-effective and computationally efficient genomic evaluation of populations of polytocous animals such as purebred pigs.

Antibiotics have been widely used in piglet diets to promote growth performance and reduce diarrhea incidence. However, the resistance of pathogens to antibiotics and the risk of residues of antibiotics in animal products induced a growing interest in the use of alternatives to in-feed antibiotics. Chito-oligosaccharide (COS), a natural alkaline polymer of glucosamine is currently being tested as a substitute for in-feed antibiotics. In weaned piglets, COS has positive effects on promoting growth, which may be related to its action on intestinal morphology, immune ability and beneficial microbiota. However, previous studies shown variable results with effective doses ranging from 30 mg/kg to 5 g/kg. Therefore, the goal of this study was to test the hypothesis that the use of COS can be an alternative to in-feed antibiotics by improve the intestinal morphology of piglets, using the jejunal explant model. The intestinal explants were exposed for 4 h to following treatments: control – only culture media and culture media with COS in doses of 0.025 mg/ml, 0.05 mg/ml, 0.1 mg/ml and 0.15 mg/ml. After the incubation period the explants were processed for histological and morphometrical analysis. The histological changes were evaluated using an adapted histological score based on the intensity and severity of lesions. Mild histological changes were observed in jejunal explants exposed to different treatments; however, no significant difference in the histological score, villi height, crypt depth or villus : crypt ratio were observed between the COS-groups and the control. In addition, goblet cells density in intestinal explants exposed to COS remained statistically similar to control group. Our results indicate that COS exposure in levels ranging from 0.025 to 0.15 mg/ml induced no effect on intestinal morphology of pig’s explants. The research will provide guidance on the low dosage of COS supplementation on weaning pigs.

Estimating the feed intake of grazing herbivores is critical for determining their nutrition, overall productivity and utilization of grassland resources. A 17-day indoor feeding experiment was conducted to evaluate the potential use of Medicago sativa as a natural supplement for estimating the total feed intake of sheep. A total of 16 sheep were randomly assigned to four diets (four sheep per diet) containing a known amount of M. sativa together with up to seven forages common to typical steppes. The diets were: diet 1, M. sativa + Leymus chinensis + Puccinellia distans; diet 2, species in diet 1 + Phragmites australis; diet 3, species in diet 2 + Chenopodium album + Elymus sibiricus; and diet 4, species in diet 3 + Artemisia scoparia + Artemisia tanacetifolia. After faecal marker concentrations were corrected by individual sheep recovery, treatment mean recovery or overall recovery, the proportions of M. sativa and other dietary forages were estimated from a combination of alkanes and long-chain alcohols using a least-square procedure. Total intake was the ratio of the known intake of M. sativa to its estimated dietary proportion. Each dietary component intake was obtained using total intake and the corresponding dietary proportions. The estimated values were compared with actual values to assess the estimation accuracy. The results showed that M. sativa exhibited a distinguishable marker pattern in comparison to the other dietary forage species. The accuracy of the dietary composition estimates was significantly (P < 0.001) affected by both diet diversity and the faecal recovery method. The proportion of M. sativa and total intake across all diets could be accurately estimated using the individual sheep or the treatment mean recovery methods. The largest differences between the estimated and observed total intake were 2.6 g and 19.2 g, respectively, representing only 0.4% and 2.6% of the total intake. However, they were significantly (P < 0.05) biased for most diets when using the overall recovery method. Due to the difficulty in obtaining individual sheep recovery under field conditions, treatment mean recovery is recommended. This study suggests that M. sativa, a natural roughage instead of a labelled concentrate, can be utilized as a dietary supplement to accurately estimate the total feed intake of sheep indoors and further indicates that it has potential to be used in steppe grassland of northern China, where the marker patterns of M. sativa differ markedly from commonly occurring plant species.

Mammary development takes place during the growing and gestation periods in swine but it also continues after farrowing. In fact, a significant proportion of mammary accretion occurs during lactation and is stimulated by suckling. After piglets are weaned, there is involution of the mammary glands and the process of mammogenesis starts again during the next parity. Suckling of a teat for the first 12 to 14 h after farrowing is not sufficient to maintain lactation, and mammary involution accompanied by alterations in gene transcription will take place. The involution process is reversible within 1 day postpartum but is not reversible if a mammary gland is unsuckled for 3 days. Mammary glands that undergo involution early in lactation do not show further involution in the post-weaning period. The action of a teat being suckled does not only affect mammary development in the ongoing lactation but it also impacts mammogenesis in the following lactation. Indeed, when a mammary gland is not suckled in first parity it has a diminished development and lower milk yield in second parity. Furthermore, it was shown that suckling of a teat for only the first 2 days postpartum in primiparous sows is sufficient to ensure optimal mammary development and milk yield from that teat in the next lactation. The behavior of nursing piglets in early lactation is also affected by whether or not a teat was previously used. Such knowledge on lactation biology is essential in order to develop the best adapted management strategies for the currently used hyperprolific sow lines and to optimize growth rate of their piglets. This review gives an update on the role of suckling for mammary development in lactating sows and on how it can affect management strategies of primiparous sows.

Although only a few specific pigmentation types are allowed within the Hucul horse registry, accurate determination of particular coat colors can be uncertain due to the presence of variation in color shades and segregation of multiple dun dilution variants. Herein, we genotyped the previously identified polymorphisms within two coat color loci TBX3 (T-box 3) and ASIP (Agouti Signaling Protein) in 462 Hucul individuals and compared the genotype predicted phenotypes with observed pigmentation types provided in the Polish Horse Breeders Association database. We identified disagreement between the predicted and recorded coat color in 157 horses (34%). The most common error was misclassification of horses with the nd1/nd1 and nd1/nd2 genotypes, what may be related with the occurrence of some ‘intermediate’ dilution phenotypes in such individuals. We have also proven that the frequency of the dominant dun dilution allele (D) (0.30) is higher than previously predicted by available studbooks. The D allele(s) is easily ‘hidden’ in various phenotypic groups including dark bay and black, therefore we hypothesized that the dun dilution effect itself is not as strongly epistatic in the Hucul horse as described in other horse breeds. This may be the result of an additional genetic modifier suppressing D allele phenotypic effect.

The development of nutritional strategies to improve microbial homeostasis and gut health of piglets post-weaning is required to mitigate the high prevalence of post-weaning diarrhea and subsequent growth checks typically observed during the weaning transition. Therefore the objective of this study was to determine the effect of supplementing piglet creep and nursery feed with a yeast-derived mannan-rich fraction (MRF) on piglet growth performance, cecal microbial profiles, and jejunal morphology and gene expression. Ten litters of piglets (n=106) were selected on postnatal day (PND) 7 and assigned to diets with or without MRF (800 mg/kg) until weaning (n=5 litters/treatment; initial weight 3.0±0.1 kg). On PND 21, 4 piglets per litter (n=40) were selected and weaned into the nursery where they remained on their respective diets until PND 42. A two-phase feeding program was used to meet nutrient requirements, and pigs were switched from phase 1 to phase 2 on PND 28. Feed intake and piglet weights were recorded on PND 7, 14, 21, 28, 35 and 42. On PND 28 and 42, ten piglets per treatment were euthanized to collect intestinal tissue and digesta. Piglets supplemented with MRF had 21.5% greater (P<0.05) average daily feed intake between PND 14-21. However, MRF supplementation did not affect piglet growth performance compared to control. On PND 28, jejunal villus height was 16.8% greater (P<0.05) in piglets consuming MRF supplemented diets. Overall microbial community structure in cecal digesta on PND 28 tended to differ in pigs supplemented with MRF (P=0.076; analysis of similarities (ANOSIM)) with increased (P<0.05) relative abundance of Paraprevotellaceae genera YRC22 and CF231, and reduced (P<0.05) relative abundance of Sutterella and Prevotella. Campylobacter also tended to reduce (P<0.10) in MRF supplemented piglets. On PND 28 differential gene expression in jejunal tissue signified an overall effect of supplementing MRF to piglets. Downstream analysis of gene expression data revealed piglets supplemented with MRF had enriched biological pathways involved in intestinal development, function and immunity, supporting the observed improvement in jejunal villus architecture on PND 28. On PND 42 there was no effect of MRF supplementation on jejunal morphology or overall cecal microbial community structure. In conclusion, supplementing Actigen™, a MRF, to piglets altered cecal microbial community structure and improved jejunal morphology early post-weaning on PND 28, which is supported by enrichment of intestinal development pathways.

Gut microbes, especially those in the large intestine, are actively involved in nutrient metabolism; however, their impact on host nitrogen (N) metabolism remains largely unknown. This study was designed to investigate the effects of feeding a cocktail of antibiotics (AGM) (ampicillin, gentamycin and metronidazole) on intestinal microbiota, N utilization efficiency, and amino acid (AA) digestibility in cannulated pigs, with the aim of exploring the impact of gut microbiota on host N metabolism. In total, 16 piglets were surgically fitted with a simple distal ileal T-cannula and a jugular venous catheter. The pigs were fed a basal diet without antibiotics (control; CON) or with antibiotics (antibiotic; ANTI), for 2 weeks. The results showed that feeding AGM did not affect weight gain or digestive enzyme activity. The antibiotics increased the concentration of urea N (P<0.05). However, they reduced N utilization, and the total tract apparent digestibility of isoleucine, methionine, valine, tyrosine and total AA (P<0.05). Furthermore, the antibiotics increased the terminal ileum apparent digestibility of CP, phenylalanine, valine, alanine, tyrosine and total AA (P<0.05). AGM markedly altered the composition of the microbiota in the ileum and feces, with a reduction in populations of Bifidobacterium, Lactobacillus and Ruminococcus, and an increase in the abundance of Escherichia coli (P<0.05). The antibiotics also significantly increased the concentration of cadaverine and ammonia, both in ileal digesta and feces (P<0.05), suggesting a marked impact on N metabolism in the intestine. The analyses indicated that the alteration of gut microbiota was correlated with the apparent digestibility of CP and AA in the intestine. These findings suggest that the AGM-induced alteration of gut microbiota may contribute to the change in intestinal N metabolism, and consequently, N excretion from the body. These results also suggest that antibiotics could have a significant effect on host N metabolism. The present study contributes to our understanding of the effects of antibiotics and provides a rational scientific basis for diet formulation during AGM use.

Dietary protein restriction is one of the effective ways to reduce post-weaning diarrhoea and intestinal fermentation in piglets, but it may also reduce growth performance. The compensatory growth induced by subsequent protein realimentation may solve the issue. However, little research has been done on the impact of protein realimentation on the gut. In this study, the effects of protein restriction and realimentation on ileal morphology, ileal microbial composition and metabolites in weaned piglets were investigated. Thirty-six 28-day-old weaned piglets with an average body weight of 6.47 ± 0.04 kg were randomly divided into a control group and a treatment group. The CP level in the diet of the control group was 18.83% for the entire experimental period. The piglets in the treatment group were fed 13.05% CP between days 0 and 14 and restored to a diet of 18.83% CP for days 14 to 28. On day 14 and 28, six pigs from each group were sacrificed and sampled. It was found that the abundance of Lactobacillus and Salmonella in the ileal digesta was significantly lower in the treatment group than the control group on day 14, whereas the abundance of Clostridium sensu stricto 1, Streptococcus, Halomonas and Pseudomonas significantly increased in the ileal digesta of the treatment group on day 14 compared with the control group. In addition, reduced concentrations of lactic acid, total short-chain fatty acids (total SCFAs), total branched chain fatty acids, ammonia and impaired ileal morphology and mucosal barrier were observed in the treatment group on day 14. However, diarrhoea levels decreased in the treatment group throughout the experiment. During the succedent protein realimentation stage, the treatment group demonstrated compensatory growth. Compared with the control group, the treatment group showed increased abundance of Lactobacillus and reduced abundance of Salmonella, Halomonas and Pseudomonas in the ileum on day 28. The concentrations of lactic acid and total SCFAs increased significantly, whereas the concentration of ammonia remained at a lower level in the treatment group on day 28 compared with the control group. Overall, protein realimentation could improve ileal morphology and barrier functions and promote ileal digestive and absorptive functions. In conclusion, ileal microbial composition and metabolites could change according to dietary protein restriction and realimentation and eventually influence ileal morphology and barrier functions.

Recent researches have showed that probiotics promote bone health in humans and rodents. The objective of this study was to determine if probiotics have the similar effects in laying hens. Ninety-six 60-week-old White Leghorn hens were assigned to four-hen cages based on their BW. The cages were randomly assigned to 1 of 4 treatments: a layer diet mixed with a commercial probiotic product (containing Enterococcus faecium, Pediococcus acidilactici, Bifidobacterium animalis and Lactobacillus reuteri) at 0, 0.5, 1.0 or 2.0 g/kg feed (Control, 0.5×, 1.0× and 2.0×) for 7 weeks. Cecal Bifidobacterium spp. counts were higher in all probiotic groups (P<0.001) compared with the control group. The percentage of unmarketable eggs (cracked and shell-less eggs) was decreased in both 0.5× and 2.0× groups compared with the control group (P=0.02), mainly due to the reduction of shell-less eggs (P=0.05). The increases in tibial and femoral mineral density and femoral mineral content (P=0.04, 0.03 and 0.02, respectively), with a concomitant trend of increases in humerus mineral density and tibial mineral content (P=0.07 and 0.08, respectively), occurred in the 2.0× group. However, the bone remodeling indicators of circulating osteocalcin and c-terminal telopeptide of type I collagen were similar among all groups (P>0.05). In addition, the plasma concentrations of cytokines (interleukin-1β, interleukin-6, interleukin-10, interferon-γ and tumor necrosis factor-α) and corticosterone as well as the levels of heterophil to lymphocyte ratio were similar between the 2.0× group and the control group (P>0.05). In line with these findings, no differences of cecal tonsil mRNA expressions of interleukin-1β, interleukin-6 and lipopolysaccharide-induced tumor necrosis factor-α factor were detected between these two groups (P>0.05). These results suggest that immune cytokines and corticosterone may not involve in the probiotic-induced improvement of eggshell quality and bone mineralization in laying hens. In conclusion, the dietary probiotic supplementation altered cecal microbiota composition, resulting in reduced shell-less egg production and improved bone mineralization in laying hens; and the dietary dose of the probiotic up to 2.0× did not cause negative stress reactions in laying hens.

Excessive abdominal fat might be associated with more severe metabolic disorders in Holstein cows. Our hypothesis was that there are genetic differences between cows with low and high abdominal fat deposition and a normal cover of subcutaneous adipose tissue. The objective of this study was to assess the genetic basis for variation in visceral adiposity in US Holstein cows. The study included adult Holstein cows sampled from a slaughterhouse (Green Bay, WI, USA) during September 2016. Only animals with a body condition score between 2.75 and 3.25 were considered. The extent of omental fat at the level of the insertion of the lesser omentum over the pylorus area was assessed. A group of 100 Holstein cows with an omental fold <5 mm in thickness and minimum fat deposition throughout the entire omentum, and the second group of 100 cows with an omental fold ⩾20 mm in thickness and with a marked fat deposition observed throughout the entire omentum were sampled. A small piece of muscle from the neck was collected from each cow into a sterile container for DNA extraction. Samples were submitted to a commercial laboratory for interrogation of genome-wide genomic variation using the Illumina BovineHD Beadchip. Genome-Wide association analysis was performed to test potential associations between fat deposition and genomic variation. A univariate mixed linear model analysis was performed using genome-wide efficient mixed model association to identify single nucleotide polymorphisms (SNPs) significantly associated with variation in a visceral fat deposition. The chip heritability was 0.686 and the estimated additive genetic and residual variance components were 0.427 and 0.074, respectively. In total, 11 SNPs defining four quantitative trait locus (QTL) regions were found to be significantly associated with visceral fat deposition (P<0.00001). Among them, two of the QTL were detected with four and five significantly associated SNPs, respectively; whereas, the QTLs detected on BTA12 and BTA19 were each detected with only one significantly associated SNP. No enriched gene ontology terms were found within the gene networks harboring these genes when supplied to DAVID using either the Bos taurus or human gene ontology databases. We conclude that excessive omental fat in Holstein cows with similar body condition scores is not caused by a single Mendelian locus and that the trait appears to be at least moderately heritable; consequently, selection to reduce excessive omental fat is potentially possible, but would require the generation of predicted transmitting abilities from larger and random samples of Holstein cattle.

The replacement of the finite and costly resource fish oil is an important task for aquaculture nutrition. A promising approach could be the use of plant bioactives that may have the potential to influence the metabolism and the synthesis of n-3 long chain polyunsaturated fatty acids, especially EPA (20:5n-3) and DHA (22:6n-3). In this study, the two phytochemicals resveratrol (RV) and genistein (G) were investigated for their effects on fish growth, nutrient utilization and body nutrient composition alongside their effects on whole body fatty acid (FA) composition. In a feeding trial lasting 8 weeks, rainbow trout (initial BW: 81.4±0.5 g) were held in a recirculating aquaculture system and fed six experimental diets with varying fish oil levels as plain variants or supplemented with 0.3% of dry matter (DM) of either RV or G. The six diets were as follows: diet F4 had 4% DM fish oil, diet F0 had 0% DM fish oil, diets F4+RV, F4+G, F0+RV and F0+G were equal to the diets F4 and F0, respectively, and supplemented with the phytochemicals RV and G. The feeding of the F0+RV diet resulted in reduced feed intake, growth rate and slightly reduced whole body lipid levels. At the same time, the amount of polyunsaturated FA and the n-3/n-6 ratio were significantly increased in whole body homogenates of rainbow trout fed diet F0+RV in comparison to the F0 control. The feeding of the F0+G diet led to reduced feed intake, slightly increased protein utilization but did not significantly affect the whole body FA composition. Overall, feeding the fish oil-free diet supplemented with the phytochemicals resulted in more pronounced effects on fish performance and FA composition than the single factors per se (dietary fish oil level or phytochemical). Present data indicate that G might not be of profitable use for trout nutrition. In terms of FA composition, RV could be a potentially useful complement for fish oil. However, the impairment of growth and performance parameters as observed in the present study discourages its use in trout diets.

Protein is the most costly nutrient in fish feed, and while diets offered in the early stages of development typically have high levels of CP, they do not always correspond to the real requirements of the animals. Thus, research that seeks to learn the true nutritional requirements of fish is fundamental to improving commercial fish culture. The present study evaluated the protein requirements of Nile tilapia (Oreochromis niloticus) under larviculture. Fish performance, gene expression for digestive enzymes and their enzymatic activity and stress response to air exposure were analyzed. Four experimental diets differing in CP level were formulated: 30%, 36%, 42% and 48%. Fish larvae were fed the experimental diets during development and sampled 10, 20 and 30 days after the beginning of the experiment for performance, gene expression and enzymatic activity. At sampling time 30, stress resistance was also evaluated by means of an air exposure test. At sampling time 10, CP levels between 36% and 48% could be used for a better performance. During this period, pepsinogen expression was greater for 30% CP, intermediate for 42% and lower for 36% and 48%. After this initial period, diets of between 30% and 42% CP are recommended for better performance. At sampling time 20, gene expression for digestive enzymes and their enzymatic activity were similar for all diets tested. At sampling time 30, the diet of 42% CP induced both greater pepsinogen expression and pepsin activity. Survival after the air exposure test after 30 days of feeding was influenced by CP level in the diet, with the highest survival being for fish fed with 36% CP. Taken together, the present results demonstrate that dietary CP influences digestive enzyme gene expression and activity, and suggest that the best CP levels for Nile tilapia larviculture vary depending on larval stage.