The objectives of the two experiments were to determine the respective effects and interactions of diet type (grass v. maize diets) and physical activity (grazing v. zero grazing) on lipogenic enzyme activities and adipose cell size in subcutaneous, perirenal and intermuscular adipose tissues and on plasma metabolites and hormones in Charolais steers. After weaning, the steers were assigned to two (Experiment 1, n = 24) or three (Experiment 2, n = 24) groups, with steers in Experiment 1 grazed grass or indoors maize-silage-fed and steers in Experiment 2 grazed grass, indoors cut grass- or indoors maize-silage-fed. Both experiments lasted for 23 months. All grass-fed animals were fed grass silage during the two winter seasons. During the two summer seasons, steers fed on grass were rotationally grazed on a perennial rye-grass pasture while steers fed on cut grass were fed indoors on freshly cut grass alone. Steers fed on maize silage were fed maize silage indoors during the entire experiment. All animals were reared for similar body weight and growth rates and slaughtered at the same age (31 to 32 months). Activities of lipogenic enzymes were significantly lower in the three adipose tissue sites of steers fed cut grass compared with maize silage, although there were less-marked effects in intermuscular adipose tissue. Plasma insulin and glucose concentrations were also lower in steers fed cut grass whereas plasma leptin concentration was similar. As body fat content was not affected by nutritional treatment, it is suggested that the decrease in potential lipogenic activity was associated with the nature of the diet and not to differences in available net energy. In other respects, grazed grass compared with eating cut grass did not affect lipogenic enzyme activities but decreased plasma leptin concentrations in the older steers and increased plasma non-esterified fatty acids and glucose concentrations without affecting adipose tissue weight and adipose cell size.

The experiment consisted of a 2 × 2 × 2 factorial design testing the two D+ and D− chicken lines selected for divergent digestion efficiency (fifth selection generation), xylanase (with or without) and ampicillin and collistin (with or without) supplementations. From 8 to 22 days, 144 chickens (18 birds per treatment) were fed a diet containing 55% wheat from a high-viscosity cultivar (Rialto). Effects of treatments were evaluated on individual growth performance (8 to 19 days), digestibilities of lipids and dry matter, dietary energy value (apparent metabolisable energy corrected to zero-nitrogen retention (AMEn)), digestive organ and breast sizes, and intestinal bile acids at 3 weeks of age. Individual variabilities were much lower in D+ than in D− birds for feed : gain ratios, digestibilities and AMEn values. In all cases, feed : gain ratios were lower in the D+ than in the D− line (P < 0.001), and D+ birds showed 22% to 86% higher values than in D− birds (P < 0.001) for digestibilities and AMEn. In D− birds, antibiotics but not xylanase supplementation had significant effects on lipid digestibility (P < 0.01) and AMEn (P < 0.05), whereas both supplements improved these parameters in D+ birds (P < 0.001 for both additives on lipids digestibility, P < 0.05 for xylanase and P < 0.01 for antibiotics on AMEn). Relative weights of gizzard and proventriculus, and gizzard : intestine weight ratio were higher in D+ than in D− birds, while relative weight of intestine was increased in D− birds compared with D+ birds. Antibiotics reduced intestine relative weight in D+ (P < 0.001) and D− (P < 0.01) lines. AMEn variations were efficiently predicted by the gizzard : intestine weight ratio. In conclusion, antibiotics were very efficient for improving growth performance, AMEn and digestibility values in both chicken lines. Xylanase was less efficient than antibiotics. Because of their low individual variabilities, D+ birds were much more efficient than D− ones for the detection of significant effects induced by xylanase supplementation. Differences between lines in feed : gain ratio, digestibilities and AMEn were reduced when xylanase and antibiotics were added together. Effects of xylanase supplementation and animal genetics on lipid digestibility could not be entirely explained in terms of intestinal bile acids. Other factors should be involved, especially for the lipid digestibility difference induced by animal genetics. The gizzard : intestine weight ratio was an efficient parameter for predicting AMEn variations due to animal genetics and additives.

Previously, feeding fish oil (FO) and sunflower seeds to dairy cows resulted in the greatest increases in the concentrations of vaccenic acid (VA, t11 C18:1) and conjugated linoleic acid (CLA) in milk fat. The objective of this study was to evaluate the effects of forage level in diets containing FO and sunflower oil (SFO) on the production of trans C18:1 and CLA by mixed ruminal microbes. A dual-flow continuous culture system consisting of three fermenters was used in a 3 × 3 Latin-square design. Treatments consisted of (1) 75:25 forage:concentrate (HF); (2) 50:50 forage:concentrate (MF); and (3) 25:75 forage:concentrate (LF). FO and SFO were added to each diet at 1 and 2 g/100 g dry matter (DM), respectively. The forage source was alfalfa pellets. During 10-day incubations, fermenters were fed treatment diets three times daily (140 g/day, divided equally between three feedings) as TMR diet. Effluents from the last 3 days of incubation were collected and composited for analysis. The concentration of trans C18:1 (17.20, 26.60, and 36.08 mg/g DM overflow for HF, MF, and LF treatments, respectively) increased while CLA (2.53, 2.35, and 0.81 mg/g DM overflow) decreased in a linear manner ( P < 0.05) as dietary forage level decreased. As dietary forage levels decreased, the concentrations of t10 C18:1 (0.0, 10.5, 33.5 mg/g DM) in effluent increased ( P < 0.05) and t10c12 CLA (0.08, 0.12, 0.35 mg/g DM) tended to increases ( P < 0.09) linearly. The concentrations of VA (14.7, 13.9, 0.0 mg/g DM) and c9t11 CLA (1.78, 1.52, 0.03 mg/g DM) in effluent decreased in a linear manner ( P < 0.05) as dietary forage levels decreased. Decreasing dietary forage levels resulted in t10 C18:1 and t10c12 CLA replacing VA and c9t11 CLA, respectively, in fermenters fed FO and SFO.

The purpose of the present study was to compare the influence of adding no or 8% fat of varying sources (coconut oil, fish oil, rapeseed oil and sunflower oil) to diets for sows 1 week prior to farrowing and during lactation on the composition of fatty acids in plasma and tissues of the progeny while sucking and 3 weeks after weaning from the sow. A control diet without supplemental fat and four diets supplemented with 8% of coconut oil, rapeseed oil, fish oil or sunflower oil were provided to lactating sows (n = 15), and during the post-weaning period the same weaner diet was provided to all piglets (n = 15 litters), which were housed litterwise. The dietary ratio of n-6:n-3 fatty acids of the maternal diets largely influenced the progeny, as the ratio varying from 1.2 (fish oil) to 12.2 (sunflower oil) in the sow milk was reflected in plasma and adipose tissues of the sucking progeny. The liver showed similar variations according to dietary treatments, but a lower n-6:n-3 fatty acids ratio. From day 4 to later on during the suckling period, the concentration of C14:0, C16:0 and C18:1 in the liver of the piglets decreased, irrespective of the dietary treatments of sows. In plasma and liver, the total concentration of saturated fatty acids (SAFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA) did not differ markedly in piglets sucking sows fed different dietary fatty acids, whereas the adipose tissue of piglets sucking sows fed sunflower oil and coconut oil showed the highest proportion of PUFA and SAFA, respectively. Weaning lowered the concentration of lipid-soluble extracts in plasma and the concentration of fatty acids in the liver of the piglets. Within the post-weaning period, dietary treatments of sows, rather than age of piglets, influenced the fatty acid composition of plasma and adipose tissue of the piglets, whereas the hepatic fatty acid profile was more affected by the age of the piglets during the post-weaning period. This study shows that the fatty acid profile of plasma and tissues of the progeny is highly dependent on the maternal dietary composition, and that the dietary impact persists for up to 3 weeks after the suckling period.

A 2 × 2 factorial experiment was performed to investigate the interaction between a high- and low-crude-protein (CP) diet (200 v. 140 g/kg) and inulin supplementation (0 v. 12.5 g/kg) on nutrient digestibility, nitrogen (N) excretion, intestinal microflora, volatile fatty acid (VFA) concentration and manure ammonia emissions from 24 boars (n = 6, 74.0 kg live weight). The diets were formulated to contain similar concentrations of digestible energy and lysine. Pigs offered the high-CP diets had a higher excretion of urinary N (P < 0.001), faecal N (P < 0.01) and total N (P < 0.001) than the pigs offered the low-CP diets. Inulin supplementation increased faecal N excretion (P < 0.05) and decreased the urine N : faeces N ratio (P < 0.05) compared with the inulin-free diets. There was no effect (P > 0.05) of dietary treatment on N retention. There was an interaction (P < 0.05) between dietary CP concentration and inulin supplementation on caecal Enterobacteria spp. Pigs offered the diet containing 200 g/kg of CP plus inulin decreased the population of Enterobacteria spp. compared to those with the inulin-supplemented 140 g/kg CP diet. However, CP level had no significant effect on the population of Enterobacteria spp. in the unsupplemented diets. Inulin supplementation increased caecal Bifidobacteria (P < 0.01) compared with the inulin-free diets. There was no effect of inulin supplementation on VFA concentration or intestinal pH (P > 0.05). Pigs offered the 200 g/kg CP diets had higher (P < 0.05) manure ammonia emissions from 0 to 240 h of storage than pigs offered the 140 g/kg CP. In conclusion, inulin supplementation resulted in an increase in Bifidobacteria concentration and a reduction in Enterobacteria spp. at the high CP level indicating that inulin has the ability to beneficially manipulate gut microflora in a proteolytic environment.

The origin of myristic acid in mammalian cells and the regulation of its endogenous cellular low concentration are not known. Another intriguing question is the potential metabolic properties of endogenous myristic acid as compared with exogenous myristic acid. In the present paper, we hypothesised and demonstrated that, in liver cells, in addition to the usual fatty acid synthase (FAS) pathway that produces predominantly palmitic acid and minor amounts of myristic acid, part of endogenous cellular myristic acid also comes from a shortening of palmitic acid, likely by peroxisomal β-oxidation and from lauric acid by elongation. From a nutritional point of view, C16:0 is universally found in natural fats and its shortening to myristic acid could contribute to a non-negligible source of this fatty acid (FA) in the organism. Then, we measured the distribution of endogenously synthesised myristic acid in lipid species and compared it with that of exogenous myristic acid. Our results do not support the hypothesis of different metabolic fates of endogenous and exogenous myristic acid and suggest that whatever the origin of myristic acid, its cellular concentration and lipid distribution are highly regulated.

Relationships between genetic merit for milk production and animal parameters and various parameters of reproductive performance were examined using multilevel binary response analysis in a study of 19 dairy herds for three successive years, representing approximately 2500 cows per year. The proportion of cows intended for rebreeding that were back in-calf again within 100 days of calving (ICR-100) and the proportion of cows that reappeared again with 365 (RR-365) and 400 days (RR-400) of a previous calving were considered in addition to the traditional measures of reproductive performance. Each 100-kg increase in genetic merit for milk yield was associated with an increased interval to first service (IFS) and calving index (CI) of 1.4 ( P < 0.001) and 1.8 days ( P < 0.001), respectively, a 0.5% increase ( P < 0.05) in calving rate to first insemination (CR-1) and 0.8% increase in RR-400. Each £10 increase in £PIN (the economically weighted yield selection index used in the UK that takes account of butterfat and protein yields) was associated with an increased IFS and CI of 1.5 ( P < 0.001) and 3.0 days ( P < 0.001), respectively. Cows with increased genetic merit for milk yield and £PIN were more likely to re-calve (RR-overall; P < 0.001). Each 1000-kg increase in 305-day milk yield was associated with an increased IFS and CI of 3.2 ( P < 0.001) and 7.8 days ( P < 0.001), respectively, and a 13.6 ( P < 0.001), 22.4 ( P < 0.001), 19.9 ( P < 0.001) and 19.0% ( P < 0.001) decrease in CR-1, ICR-100, RR-365 and RR-400, respectively. A 10-kg increase in maximum yield was associated with a 6.6-day increase in CI ( P < 0.001) and a 14.9 ( P < 0.001), 18.3 ( P < 0.001), 9.6 ( P < 0.05) and 14.2% ( P < 0.001) decrease in CR-1, ICR-100, RR-365 and RR-400, respectively. Fertility performance was also associated with season of calving, lactation number and dystocia score. Level of production had a larger effect on fertility performance than genetic merit for milk production suggesting that infertility at an individual cow level is more likely to be associated with increased production and an inability to meet the nutritional requirements of the cow.

Nutritional requirements of the Iberian pig, a slow-growing, obese porcine breed, are not well defined and seem to differ from those of conventional or high-performing pigs. The effects of the dietary protein content and the feeding level on the utilisation of metabolisable energy (ME) and the rates of gain, protein, and fat deposition were studied with 81 Iberian castrates growing from 50 to 100 kg body weight (BW) by using the comparative slaughter technique. The animals were fed 4 diets providing 145, 120, 95, and 70 g ideal crude protein (CP) per kg dry matter (DM), and containing 13.94, 14.29, 14.56, and 14.83 MJ ME per kg DM, respectively. Three levels of feeding were evaluated: 0.60, 0.80, and 0.95 × ad libitum intake. Growth rate increased (linear and quadratic, P < 0.001) as the dietary ideal CP content decreased. It also increased with the feeding level (linear, P < 0.001; quadratic, P < 0.05). Gain:feed and gain:ME intake improved by decreasing the ideal CP content in the diet (linear, P < 0.001 and P < 0.05, respectively; quadratic P < 0.001 for both variables). Increasing the feeding level improved linearly gain:feed and gain:ME intake ( P < 0.001). Protein deposition (PD):ME intake ranged between 1.23 and 1.44 g/MJ, and it showed a tendency to reach the maximum value when the diet providing 95 g ideal CP per kg DM was fed (quadratic, P = 0.078). When this diet was offered at 0.95 × ad libitum, PD reached a maximum value of 71 g/day. This dietary treatment resulted in average values for average daily gain and retained energy (RE) of 854 g/day and 21.4 MJ/day, respectively. The average rate of gain was 19.93 g/MJ increase in ME intake, equivalent to an energy cost of 50.2 kJ ME per g gain, irrespective of the dietary ideal CP content. Also, the overall marginal efficiency of protein deposition (ΔPD:ΔME; g/MJ) was 1.34. Increasing the feeding level led to increases in PD (linear, P <  0.001) and RE (linear, P <  0.001; quadratic, P <  0.01) irrespective of the dietary ideal CP concentrations. Between 50 and 100 kg BW, the chemical composition of 1 kg gain averaged 78, 592, 28.7, and 284 g for CP, fat, ash, and water respectively. The net efficiency of use of ME for growth ( kg) and the maintenance energy requirements were 0.606 and 396 kJ/kg BW 0.75 per day, respectively. The results support earlier findings that the genotype has marked effects on protein and energy metabolism of growing pigs and underline important compositional differences of the Iberian pig compared with conventional or modern porcine genotypes.

The effect of a dietary supplementation with mannan-oligosaccharide (MOS, Bio-Mos, Alltech Inc.) and inulin (Frutafit® IQ) on growth, health, and caecal traits was studied on 348 rabbits (Hyplus®), weaned at 25 days of age. Three hundred and thirty rabbits (110 per group) were used for the health status and growth performance trial, while 18 rabbits (six per group) were used for caecal metabolism evaluation at the age of 42 days of age. Three diets were formulated: C (control), M (0.3% MOS) and I diet (4% inulin). Digestibility of the diets was measured in 10 rabbits per group between 36 and 40 days of age. The control diet was fed to rabbits of the C group from weaning to 74 days of age (slaughter). Diets M and I were fed to rabbits of the respective group from weaning to 46 days of age, then were fed with control diet till slaughter. From 25 to 46 days of age, the weight gain was slightly higher in control rabbits ( P = 0.11), while no differences were recorded for the whole period. No differences among groups in the mortality, which was high due to an enteropathy-infected environment, were significant. The lowest morbidity ( P = 0.05) as well as the health risk index were recorded in rabbits fed the diet with inulin ( P = 0.03). After change of diet, the health risk index increased in the rabbits previously fed the diet with additives, thereby no significant differences in the health status were recorded for the whole period. Total caecal volatile fatty acids concentration was higher ( P < 0.01) and the pH ( P < 0.01) and ammonia concentration ( P = 0.01) lower in rabbits fed the inulin diet than in other rabbits. In these animals, acetate molar proportion was higher ( P = 0.01) and that of propionate as well as the propionate/butyrate ratio significantly lower than in other rabbits. Butyrate molar proportion was higher in rabbits fed the diet with MOS ( P < 0.01). In rabbits fed the inulin diet a higher activity of inulinase was recorded ( P < 0.001) than in other rabbits. A significantly lower digestibility of cellulose was observed in rabbits fed the diet with MOS. The results of our study suggest the importance of using inulin-type fructans in the nutrition of young rabbits. The higher health risk index of rabbits after change of diets indicates that prebiotics should be given for a longer time during the fattening period.

The objectives of this study were to determine true phosphorus (P) digestibility, degradability of phytate-P complex and the endogenous P outputs associated with brown rice feeding in weanling pigs by using the simple linear regression analysis technique. Six barrows with an average initial body weight of 12.5 kg were fitted with a T-cannula and fed six diets according to a 6 × 6 Latin-square design. Six maize starch-based diets, containing six levels of P at 0.80, 1.36, 1.93, 2.49, 3.04, and 3.61 g/kg per kg dry-matter (DM) intake (DMI), were formulated with brown rice. Each experimental period lasted 10 days. After a 7-day adaptation, all faecal samples were collected on days 8 and 9. Ileal digesta samples were collected for a total of 24 h on day 10. The apparent ileal and faecal P digestibility values of brown rice were affected ( P < 0.01) by the P contents in the assay diets. The apparent ileal and faecal P digestibility values increased from − 48.0 to 36.7% and from − 35.6 to 40.0%, respectively, as P content increased from 0.80 to 3.61 g/kg DMI. Linear relationships ( P < 0.05), expressed as g/kg DMI, between the apparent ileal and faecal digestible P and dietary levels of P, suggested that true P digestibility and the endogenous P outputs associated with brown rice feeding could be determined by using the simple regression analysis technique. There were no differences ( P>0.05) in true P digestibility values (57.7 ± 5.4 v. 58.2 ± 5.9%), phytate P degradability (76.4 ± 6.7 v. 79.0 ± 4.4%) and the endogenous P outputs (0.812 ± 0..096 v. 0.725 ± 0.083 g/kg DMI) between the ileal and the faecal levels. The endogenous faecal P output represented 14 and 25% of the National Research Council (1998) recommended daily total and available P requirements in the weanling pig, respectively. About 58% of the total P in brown rice could be digested and absorbed by the weanling pig. Our results suggest that the large intestine of the weanling pigs does not play a significant role in the digestion of P in brown rice. Diet formulation on the basis of total or apparent P digestibility with brown rice may lead to P overfeeding and excessive P excretion in pigs.

A multidisciplinary research programme was developed to get a scientific expertise for the quality assessment of products obtained from cloned livestock. Thirty-seven bovine Holstein female clones of five different genotypes and their products were analysed in comparison with 38 control animals obtained by conventional artificial insemination and raised under the same conditions at the same experimental farm. Animal evaluation included over 150 criteria and more than 10 000 measurements to check the physiological status and health over a 3-year period. All the parameters studied were in the normal range for age and breed, but some significant differences were detected between clone and control groups in terms of delayed onset of puberty in clones, higher neutrophil counts in haematology or lower biochemical plasma concentrations of gamma glutamyl transferase. Milk and meat analyses were conformable to expected values. We, however, found some differences in fatty acid (FA) composition of milk and muscle suggesting a possible deviation in lipid metabolism as assessed by higher delta-9 desaturase activity indexes in both milk and muscles from clones compared with controls. Repeated muscle biopsies in the semitendinosus muscle of the same animals demonstrated a higher oxidative activity in muscle of young clones (8 months of age) compared with controls, suggesting a delayed muscle maturation in clones. Nutritional evaluation of milk and meat using the rat feeding trials did not show any difference between clone and control products for food intake, growth rate, body composition of the rats, nor for possible allergenicity. Possible reactivation of bovine endogenous retroviruses (BERVs) was analysed and compared between normal and cloned cattle. As expected, these BERV sequences are not transcribed and no RNA was detected in the blood of clones, donor animals or controls; therefore, it may be assumed that the sanitary risk associated with BERV sequences is not higher in cattle derived from somatic nuclear transfer than in cattle born from conventional reproduction. Our results confirm that the quality and safety of products (milk and meat) from adult and clinically healthy cloned cattle is globally similar to normal animals. However, from a strictly biological point of view, the slightly delayed maturation we observed in the muscle of clones together with some marginal differences identified in FA composition of both muscle and milk, point to the need for more refined analysis to totally exclude any risks from the consumption of those products.

Three change-over design experiments investigated the origin of hydrogen sulphide in the rumen head-space gas of dairy cows, comparing the effects of single iso-S additions of methionine, cysteine and sodium sulphate, as well as the effects of single meals of fresh ryegrass or white clover. The concentration of hydrogen sulphide in rumen gas declined close to zero within 4 h after withdrawal of the previous feed. Sulphur sources were then given to cows and concentrations of hydrogen sulphide recorded in rumen head-space gas at 30-min intervals. Cysteine addition (8 g) led to a rapid (within 30 min) and a large (490 and 957 p.p.m. respectively in two experiments) increase in hydrogen sulphide concentration. Concentrations were significantly less following methionine addition. Increasing levels of cysteine addition led to significant increases in hydrogen sulphide concentrations ( P < 0.001 for the linear effect), although peak hydrogen sulphide was delayed and concentrations remained higher for longer with the highest (12 g) addition of cysteine ( P < 0.01 for the ‘cysteine level’ × ‘time’ interaction). The increase in concentration of hydrogen sulphide from sodium sulphate was smaller (230 p.p.m.) and slower (2 h) than for cysteine. Despite the much higher intake of cystine for white clover in comparison with perennial ryegrass ( P < 0.001), there was almost no increase in hydrogen sulphide concentration in rumen head-space gas from cows fed white clover. It seems likely that this is associated with the use of sulphur to produce thiocyanate to detoxify the hydrogen cyanide from cyanogenic white clover.

The banning in 2006 of the use of antibiotics as animal growth promoters in the European Union has increased demand from producers for alternative feed additives that can be used to improve animal production. This review gives an overview of the most common non-antibiotic feed additives already being used or that could potentially be used in ruminant nutrition. Probiotics, dicarboxylic acids, enzymes and plant-derived products including saponins, tannins and essential oils are presented. The known modes of action and effects of these additives on feed digestion and more especially on rumen fermentations are described. Their utility and limitations in field conditions for modern ruminant production systems and their compliance with the current legislation are also discussed.

The synthetic disaccharide lactulose is known to improve the intestinal microflora by stimulating the growth of selected probiotic bacteria in the gut. In our experiment the effects of lactulose in combination with the probiotic bacteria Enterococcus faecium on growth performance and morphology of the bovine intestine were examined. Calves aged 39 ± 2 days were randomised to three feeding groups (no. = 14 each group): control (L0), fed milk replacer (MR) containing E. faecium; a lactulose group (L1) containing additional 1% lactulose and a second lactulose group (L3) containing 3% lactulose dry matter. The calves were weighed weekly. After 19 weeks the calves were slaughtered and tissues were collected for histological studies. The average daily live weight gain tended to be higher (P < 0.1) for L3 (1350 g/day) than L0 (1288 g/day). Compared with L0, a reduction (P < 0.001) of ileal villus height due to lactulose treatment of approximately 14% in group L1 and 20% in L3 was determined. A significant decrease in the depth of the crypts about 12% in L1 and 8% in L3 was detected in the caecum. The surface area of lymph follicles from Peyer's patches was decreased by lactulose treatment. Results show that lactulose has an effect on the morphology of intestine. A significant effect on growth performance can not be confirmed. However, results permit the conclusion that lactulose feeding has the tendency to increase growth performance.

A study to compare two feeding systems, stall feeding (SF) and grazing plus supplementation (GR) was carried out, based on intake, performance and rumen fermentation characteristics of lambs. While SF animals received ad libitum complete feed blocks (CFB), GR animals were allowed grazing for 8 h on a pasture and supplemented with concentrate mixture at 250 g per head per day. Intake in grazing animals was determined using chromium III oxide as internal marker. Intake of dry matter (DM), crude protein (CP) and organic matter (OM) were higher ( P < 0.01) in SF than in GR animals. Similarly, digestibility of OM, CP and energy were higher ( P < 0.01) in SF animals. Average daily gain in SF animals (101 g) was significantly ( P < 0.01) higher than in GR animals (78 g) but total wool yield was similar for the two groups (856 g, SF; 782 g, GR). The pH of the rumen content, concentration of total volatile fatty acids and total activities of carboxymethyl cellulase, xylanase and esterase in the rumen liquor were similar. The concentrations (mg/dl) of total nitrogen (125, SF; 63, GR) and NH3-nitrogen (42, SF; 31, GR) were higher in SF animals than that of GR animals. A significantly higher activity ( P < 0.05) of microcrystalline cellulase (24.5 v. 7.7 units) and lower activity ( P < 0.05) of protease (309 v. 525 units), was observed in the rumen of SF animals than in GR animals. SF animals could therefore harness more energy through degradation of plant cell walls thus reducing breakdown of plant proteins as gluconeogenic source. The SF system of feeding where CFB was offered to sheep appeared superior to GR in terms of intake, nutrient utilisation and animal performance. Therefore the SF feeding system where CFB are offered to animals can be advocated as an alternative to grazing and supplementation feeding strategy for sheep production, especially where the pastures are highly eroded and need resting for regeneration or curing. The CFB feeding can also be adopted under adverse conditions like drought and famine, a common phenomenon in arid and semiarid conditions.

Effects of synchronising the availability of amino acids and glucose within a day on protein and energy metabolism were studied in growing pigs. Ten pigs of on average 54 (s.e. 1.0) kg live weight were assigned to each of two dietary treatments (synchronous v. asynchronous nutrient supply) in a change-over design. On the synchronous treatment (SYN), pigs received two balanced meals: one at 0800 h and one at 1600 h. On the asynchronous treatment (ASYN), pigs received virtually all protein at 0800 h and all carbohydrates at 1600 h. The dietary supply of ingredients and nutrients to pigs was similar for both treatments. Pigs were housed individually in respiration chambers. Faecal apparent nutrient digestibility was determined and nitrogen and energy balances were measured. Faecal apparent digestibility of energy, organic matter and non-starch polysaccharides was higher ( P < 0.05) for SYN than for ASYN. The efficiency of utilisation of digestible protein with protein gain was higher ( P = 0.001) for SYN (56.7%) than for ASYN (47.1%). The substantial decrease ( P < 0.05) in respiratory quotient and 13C enrichment of the expired CO2 after the morning meal indicated higher amino acid oxidation for ASYN than for SYN. Heat production and energy retention as fat were not affected by nutrient synchrony. In conclusion, an asynchronous availability of glucose and amino acids within a day increases amino acid oxidation, resulting in a substantial reduction in protein utilisation but with virtually no effect on fat retention.

For sustainable aquaculture, the removal of marine resource ingredients in fish diets is an important objective. While most studies focus on the replacement of fish oil by vegetable oil, little is known on the nutritional effects of presence (which corresponds to the control diet) or absence of dietary fish oil. We studied fatty acid composition of brush-border membranes and digestive enzyme activities of the intestine and measured the expression and activities of several enzymes involved in the hepatic intermediary metabolism of rainbow trout (Oncorhynchus mykiss) fed for 7 weeks with or without fish oil. The diets were pair-fed to ensure that fish fed either diet had comparable carbohydrate and protein intakes. Absence of fish oil significantly reduced growth rate, protein efficiency and plasma lipid components. Activities of intestinal digestive enzymes were significantly decreased in the anterior intestine in fish fed without fish oil. In liver, dietary fish oil removal did not affect the transcript levels or activities of the main enzymes involved in lipogenesis (fatty acid synthase) and fatty acid β-oxidation (3-hydroxyacyl-CoA dehydrogenase), glycolysis or amino acid oxidation. It lowered the expression of the genes coding for gluconeogenic enzymes (glucose-6-phosphatase and phosphoenolpyruvate carboxykinase), but their enzyme activities were not affected. The activities, but not gene expression of lipogenic enzymes, involved in NADPH and malonyl-CoA formation were also modified after fish oil removal as reflected by higher activities of isocitrate dehydrogenase/glucose-6-phosphate dehydrogenase and acetyl-CoA carboxylase enzymes. Overall, our results indicate that the intestinal digestive capacity was strongly modified by dietary fish oil removal, while hepatic intermediary metabolism was only marginally affected, in fed rainbow trout.

A growth experiment with 108 lambs (breed: German Merino Landsheep) was carried out to examine the effect of gender, body weight (BW) and feeding intensity on the deposition of Fe, Zn, Cu and Mn in the empty body (whole animal minus contents of the gastrointestinal tract and bladder). The lambs (50% female and 50% male animals) were fed at three feeding levels (‘low’, ‘medium’ and ‘high’ by varying daily amounts of concentrate and hay) and slaughtered at different final BWs (30, 45 or 55 kg). Six male and six female animals were killed at a BW of 18 kg representing the animals’ BW at the beginning of the comparative slaughter experiment. There were significant main effects for the treatments growth rate and final weight on the daily rate of accretion of the trace elements examined. Feeding intensity had a marked influence on the accretion rate for Fe (P < 0.001), Zn (P < 0.001), Cu (P < 0.001) and Mn (P = 0.003). With increasing feeding intensity (low, medium, high) the daily deposition of these trace elements increased (4.4, 5.2, 6.6 mg/day for Fe; 4.9, 5.5, 6.9 mg/day for Zn; 0.20, 0.36, 0.44 mg/day for Cu; 0.14, 0.16, 0.21 mg/day for Mn). Heavier final BW led to increased daily retention of Zn (P < 0.001) and Mn (P = 0.002). Gender had a marked influence only on the accretion rate for Zn (P < 0.001). Ram lambs had a higher daily deposition of this element than female lambs. Related to 1000 g empty body gain, the following concentrations were found for the trace elements examined: Fe 26.1 mg, Zn 30.0 mg, Cu 1.41 mg and Mn 1.04 mg. A feeding influence was given for Zn (P < 0.001) and Cu (P = 0.039). Feeding level low had higher Zn and lower Cu concentrations. Male animals showed less Fe (P < 0.001) and Zn (P = 0.034) per kg empty body gain than females.

This experiment investigated the effects of increasing the dietary content of bacterial protein meal (BPM) on the protein and energy metabolism of pigs from weaning to a live weight of 80 kg. Four litters with four castrated male pigs in each litter were used. The litters were divided into two blocks according to age. One pig from each litter was fed one of the four experimental diets. Soya-bean meal was replaced with BPM on the basis of digestible protein, and the BPM contents in the four diets were 0% (BP0), 5% (BP5), 10% (BP10) and 15% (BP15), corresponding to 0%, 17%, 35% and 52% of the digestible nitrogen (N), respectively. Four balance periods were performed, at the start of which the pigs weighed 9.5 kg, 20.7 kg, 45.3 kg and 77.2 kg, respectively. Once during each balance period, 22-h respiration experiments were performed using indirect calorimetry. Daily weight gain, feed intake and feed conversion rate were the same for all diets. The apparent digestibility of N was lower on diet BP10 than on BP0 (P = 0.002), whereas the apparent digestibility of energy was similar on all diets. The retention of nitrogen did not differ between diets and was 1.50, 1.53, 1.33 and 1.46 g N per kg0.75 per day on BP0, BP5, BP10 and BP15, respectively. Neither metabolisable energy intake nor heat production were affected by inclusion level of BPM. Retention of energy was 620 (BP0), 696 (BP5), 613 (BP10) and 664 kJ/kg0.75 per day (BP15), the differences among diets being non-significant. The N-free respiratory quotient was similar on all diets. It was concluded that the overall protein and energy metabolism in growing pigs were not affected when up to 50% of dietary N was derived from BPM.

Whole-plant winter cereals could be of great interest if used as silages for ruminant feeding as opposed to summer crops in that they would spare water resources or valorize low-input management. This study aimed to compare the feeding value of rye, barley, wheat (two genotypes) and triticale (six genotypes). The cereals were sown in October and harvested as silage in June. Forages were offered to Texel castrated sheep in order to evaluate the organic matter digestibility (OMd). The OMd of the wheat cultivars was higher (61.6%, P<0.05) than those of barley (57.2%) and rye (54.7%) but no different from that of triticale (60.6%). Within the triticale genotypes, OMd ranged from 54.7 to 62.3%. The presence of rough barbs should explain the relatively low intake of the cereals with the exception of wheat. Winter cereals provide good-quality forage for feeding ruminants. Wheat has a higher nutritional value than barley and rye and a wide variability for digestibility seems to exist within the triticale cultivars. Such variability in a species known for its ability to be cropped under limiting conditions should be explored in much greater depth as it could result in providing farmers with genotypes of good quality with an acceptable yield at a lower cost.