This study examined the genetic and phenotypic associations between finisher performance, pre-breeding body condition of the gilt, subsequent lactation feed intake and survival of the primiparous sow to farrow in the second parity. Complete data were available on ∼2200 sows, along with additional cohort and historical performance data. Genetic variation was observed for average lactation feed intake (heritability: 0.18 ± 0.04), with a significant proportion of observed variation in average intake attributable to variation in lactation length. Weight and body condition (fatness) at finishing were very highly correlated genetically (0.89 ± 0.03 and 0.90 ± 0.02) and moderately correlated phenotypically (0.58 ± 0.01 and 0.58 ± 0.01) with weight and body condition before mating. Estimates of genetic (rg) and phenotypic (rp) correlations between feed intake recorded at finishing and average lactation feed intake (LADI) were moderate (rg = 0.26 ± 0.16 and 0.42 ± 0.22) and low (rp = 0.07 ± 0.02 and 0.08 ± 0.03), with rg dependent on the models and data subsets used for lactation intake. Non-unity genetic correlations imply that different genetic control mechanisms regulate feed intake during growth and lactation. Moderate genetic correlations between lactation feed intake with live weight (TWT) or growth rate (TADG) recorded at selection and live weight before mating (0.42 ± 0.11, 0.42 ± 0.11 and 0.37 ± 0.15) were considerably higher than the corresponding phenotypic correlations for LADI with TADG or 29WT (0.09 ± 0.02 and 0.08 ± 0.02). Correlations between fatness at selection (TFAT) or mating (29FT) and LADI were negative but not significantly different from 0. Overall, these data suggest that there is exploitable genetic variation for feed intake during lactation, and that selection is possible if lactation feed intakes are recorded. However, genetic correlations suggest that early growth seems to be related to lactation feed intake capacity. There was generally no strong evidence that selection for lean growth potential in dam lines will substantially diminish sow lactation intake capacity as a correlated response.

Data on sow body weight (BW) and fatness (n = ∼2250 pregnant sows) and reproductive data (including historical: n = ∼18 000) were used to examine the genetic and phenotypic associations between body condition before and after farrowing, gestational outcomes, lactation feed intake and the gilts’ ability to survive unculled to farrow in the second parity. Within-trait genetic correlations were very high between weight (0.77 ± 0.06) and fat depth (0.91 ± 0.04) recorded before farrowing and at weaning. Litter size traits were generally uncorrelated genetically with aspects of sow BW and body condition. However, genetic correlations indicated that sows producing heavier piglets at birth had litters with increased gain (0.36 ± 0.16), and were characterised by greater weight (−0.72 ± 0.08) and fat change (−0.19 ± 0.15) during lactation, reflected to a lesser extent by lower weight (−0.12 ± 0.11) and fatness (−0.17 ± 0.10) at weaning. Genetic correlations (ra) between reproductive traits and lactation feed intake were generally low, but favourable. However, lactation intake was positively correlated with measures of sow size (ra = ∼0.55), such that selection for lactation feed intake would likely be accompanied by increased mature sow size. Phenotypic correlations (rp) showed that sow survival to the second parity (FAR12) was positively influenced by litter size and fat depth at weaning, supporting attributes of increased fatness before farrowing, less weight loss during lactation and an increased lactation intake.

DNA barcoding is an effective technique to identify species and analyze phylogenesis and evolution. However, research on and application of DNA barcoding in Canis have not been carried out. In this study, we analyzed two species of Canis, Canis lupus (n = 115) and Canis latrans (n = 4), using the cytochrome c oxidase subunit I (COI) gene (1545 bp) and COI barcoding (648 bp DNA sequence of the COI gene). The results showed that the COI gene, as the moderate variant sequence, applied to the analysis of the phylogenesis of Canis members, and COI barcoding applied to species identification of Canis members. Phylogenetic trees and networks showed that domestic dogs had four maternal origins (A to D) and that the Tibetan Mastiff originated from Clade A; this result supports the theory of an East Asian origin of domestic dogs. Clustering analysis and networking revealed the presence of a closer relative between the Tibetan Mastiff and the Old English sheepdog, Newfoundland, Rottweiler and Saint Bernard, which confirms that many well-known large breed dogs in the world, such as the Old English sheepdog, may have the same blood lineage as that of the Tibetan Mastiff.

Future progress in genetic improvement and the monitoring of genetic resources in beef cattle requires a detailed understanding of the population under selection. This study examines the gene flow in the UK beef population with an uncommon breeding structure involving interaction between the beef and dairy populations. British Cattle Movement Service records were used as the primary source of information, and these data were triangulated with UK government statistics, other industry information sources and existing literature to build up a profile of the UK beef industry. Estimates were made of the breed composition of suckler cows, breeding bulls and the prime slaughter population. Cross-bred animals made up 85% and 94%, respectively, of the commercial beef breeding cow and prime slaughter populations. Holstein/Friesian (through cross-breeding) made up the largest proportion of genes in both these populations with 33% and 28%, respectively. The next five most popular breeds were specialist beef breeds: Limousin (22% and 18%), Charolais (11% and 6%), Simmental (9% and 11%), Angus (7% and 8%) and Belgian Blue (6% and 6%). Combined, the top seven beef breeds accounted for 94% of beef genetics in the prime slaughter population, and 80% of this came from non-native breeds. The influence of dairy breeds in the commercial beef breeding population was highlighted by the fact that 44% of replacement commercial beef breeding females were sourced from beef-sired crosses in the dairy herd, and in total 74% of all maternal grand dams of prime slaughter animals were Holstein/Friesian. The use of selection index technology was also investigated by analysing breeding bull sale results, with the correlation between the terminal sire index and sale price of young breeding bulls being generally moderate but significant, ranging from 0.21 to 0.38 across the major beef breeds. The most influential source of genetics in the commercial suckler beef herd was natural service breeding bulls. These were mostly sourced from pedigree breeders, and accounted for 47.8% of the genetics in the prime beef population. Artificial insemination sires were responsible for 16.6% of prime beef genetics, with the remaining 35.6% coming from dairy breeds, 95% of which was Holstein/Friesian.

The objective of this study was to explore the importance of including genetic progress in milk yield when evaluating different reproductive strategies in a dairy herd by simulation modeling. The model used in this study was SimHerd V, a dynamic and mechanistic Monte Carlo simulation model of a dairy herd including young stock. A daily increasing trend describing genetic milk yield potential of the sire population was included in the model. The inaccuracy of assuming that replacement heifers have the same (milk yield) potential as the cows present in the herd was hereby dealt with. Improving estrus detection rate from 0.45 to 0.80 increased gross margin (GM) per cow-year by €20 when genetic progress was not included in the model. When genetic progress was included in the model, then the same improvement in estrus detection decreased the GM per cow-year by €7.4. This reduced effect was explained by a lower replacement rate in consequence of the improved estrus detection and thereby a slower genetic progress in the herd. There was a reduced effect of including genetic progress on GM when surplus heifers were sold selectively based on breeding values. Repeated insemination with sexed semen on the superior half of all heifers reduced GM by €8 per cow-year when genetic progress was not included and increased the GM by €16 per cow-year when genetic progress was included in the model. Including genetic progress reduced the losses caused by lower conception and estrus detection rates and had a minimal effect with regard to postponing first insemination. This study has proven that it is important to include genetic progress in decisions on reproduction strategies in a dairy herd.

The objective of this study was to compare linear models and survival analysis for genetic evaluation of ovulatory disorders, which included veterinary treatments of silent heat/anestrus and cystic ovaries. Data of 23 450 daughters of 274 Austrian Fleckvieh sires were analyzed. For linear model analyses, ovulatory disorders were defined as a binary response (presence or absence) in the time periods from calving to 150 days after calving and from calving to 300 days after calving. For survival analysis, ovulatory disorders were defined either as the number of days from calving to the day of the first treatment for an ovulatory disorder (uncensored record) or from calving to the day of culling, or the last day of the period under investigation (until 150 or 300 days after calving; censored record). Estimates of heritability were very similar (0.016 to 0.020) across methods and periods. Correlations between sire estimated breeding value from linear model and survival analysis were 0.98, whereas correlations between different time periods were somewhat lower (0.95 and 0.96). The results showed that the length of time period had a larger effect on genetic evaluation than methodology.

This study was conducted to determine the effects of soy isoflavones on changes in body and tissue weight and on insulin-like factor I (IGF-I) and peroxisome proliferator-activated receptor-γ (PPARγ) gene and protein expression in muscle and adipose tissues in Chinese Guangxi minipig, as a model for studying human nutrition. A total of 72 male Chinese Guangxi minipigs were fed basal diet (control, Con), low dose of soy isoflavones and high dose of soy isoflavones (HSI). The results showed that HSI increased the body weight (BW) gain and fat percentage of minipigs (P < 0.05). In addition, the serum concentrations of IGF-I and interleukin-6 were increased by high levels of soy isoflavones (P < 0.05). Furthermore, a diet containing soy isoflavones enhanced IGF-I mRNA expression levels in longissimus muscle, but decreased these levels in perirenal fat. However, the mRNA and protein expression levels of PPARγ in longissimus muscle and subcutaneous adipose tissue were both increased when compared with the Con. The data indicated that soy isoflavones regulated the BW gain and fat percentage of Chinese Guangxi minipigs, which also showed changes in IGF-I system and PPARγ. However, further research is required to clarify the causative relationship.

The effect of dietary lipids and Clostridium butyricum supplementation on circulating lipids and the transcription of selected genes involved in lipid metabolism were investigated in broiler chickens. One hundred and sixty-day-old broilers (Arbor Acres) were divided into four treatment groups in a 2 × 2 factorial arrangement and fed four diets with two lipid sources (soybean oil or fish oil) and two levels of C. butyricum (0 or 5 g/kg) for a period of 6 weeks. Serum concentrations of total cholesterol and low-density lipoprotein cholesterol were lower (P < 0.05) in broilers fed diets containing fish oil than in those fed diets containing soybean oil. Fish oil significantly reduced (P < 0.05) hepatic fatty acid synthase and lipoprotein lipase (LPL) activities in abdominal fat. In contrast, fish oil significantly increased (P < 0.05) breast muscle LPL activity and hepatic peroxisome proliferator-activated receptor-α and LPL gene expression. The addition of C. butyricum significantly increased (P < 0.05) LPL activity in abdominal fat and liver-type fatty acid-binding protein gene expression in jejunal mucosa. The results of this study indicated that the reduced abdominal fat in broilers fed fish oil as observed may be due to augmented hepatic fatty acid catabolism and lower hepatic fat synthesis. The increased intramuscular fat content in breast muscle of broilers fed C. butyricum as described may be the result of enhanced fatty acid uptake.

The mucus layer covering the gut epithelium is pivotal to host defence and is affected by various dietary components. Part of the reported beneficial effect of dietary immunoglobulins (Igs) on gut health may be due to effects on the gut mucus layer. The aim was to determine whether orally administered ovine serum Ig influence goblet cell count, mucin gene expression and digesta mucin protein content in the gut of the growing rat. Fourteen Sprague–Dawley male growing rats were used in a 21-day study and were fed either a casein-based control diet (CON; no Ig) or a similar diet but containing freeze-dried ovine Ig (FDOI). Daily food intake and growth rate were not affected by the dietary treatments. When compared to the rats consuming CON diet, those consuming the FDOI diet had significantly (P < 0.05) more intact and cavitated goblet cells in the intestinal villi. A similar result was found for crypt goblet cells in the small intestine and colon. Ileal Muc2, Muc3, Muc4 and stomach Muc5Ac mRNA expressions for the FDOI animals were higher (P < 0.05) compared to the the CON animals. Mucin protein content was higher (P < 0.05) in the stomach, ileum and colonic digesta of rats fed the FDOI diet. In conclusion, orally administered FDOI influenced gut mucins in the growing rat as evidenced by increased mucin gene expression and digesta mucin protein concentrations as well as an increased goblet cell count.

The objectives of this study were to investigate the effects of fish oil supplementation on performance and muscle fatty acid composition of hill lambs finished on grass-based or concentrate-based diets, and to examine the interaction with selenium (Se) status. In September 2006, 180 entire male lambs of mixed breeds were sourced from six hill farms after weaning and finished on five dietary treatments: grazed grass (GG), grass +0.4 kg/day cereal-based concentrate (GC), grass +0.4 kg/day cereal-based concentrate enriched with fish oil (GF), ad libitum cereal-based concentrate (HC) and ad libitum fish oil-enriched concentrate (HF). Within each treatment, half of the lambs were also supplemented with barium selenate by subcutaneous injection. At the start of the trial, the proportion of lambs with a marginal (<0.76 μmol/l) or deficient (<0.38 μmol/l) plasma Se status was 0.84 and 0.39, respectively. Compared with control lambs, GG lambs treated with Se had higher (P < 0.01) plasma Se levels, whereas erythrocyte glutathione peroxidase activity was higher (P < 0.01) for Se-supplemented lambs fed diets GG and GF. However, Se supplementation had no effects on any aspect of animal performance. Fish oil increased (P < 0.05) levels of 22:5n-3 and 22:6n-3 in the Longissimus dorsi of HF lambs but otherwise had no effect on the health attributes of lamb meat. There were no significant effects of fish oil on dry matter intake, animal performance or lamb carcass characteristics. Daily carcass weight gain (CWG; P < 0.001), carcass weight (P < 0.01) and conformation score (P < 0.01) increased with increasing concentrate inputs. Lambs fed concentrate-based diets achieved a higher mean CWG (P < 0.001), dressing proportion (P < 0.001) and carcass weight (P < 0.011), and were slaughtered up to 8.3 days earlier (P < 0.05) and at 1.2 kg lower (P < 0.05) live weight than pasture-fed lambs. However, carcasses from grass-fed lambs contained lower levels of perinephric and retroperitoneal fat (P < 0.05), and had less fat over the Iliocostalis thoracis (P < 0.001) and Obliquus internus abdominis (P < 0.05). Meat from grass-fed lambs also had lower levels of 18:2n-6 and total n-6 fatty acids compared with those finished indoors. The results of this study demonstrate that fish oil supplementation has some benefits for the health attributes of meat from lambs fed concentrate-based diets but not grass-based diets. Supplementing Se-deficient lambs with barium selenate will improve Se status of lambs fed zero-concentrate diets, but has no additional benefit when lambs are already consuming their daily Se requirement from concentrates or when fish oil-enriched diets are fed.

The aim of this study was to evaluate whether the peripheral cytokine expression could be affected by differences in fat thickness in healthy mares during the periparturient period (last weeks of pregnancy and first weeks of lactation). At the beginning of the 11th month of gestation, 18 mares with normal body condition score (BCS; 5) were divided into two groups with low (L; ⩽12 mm; n = 12) and high (H; >12 mm; n = 6) fat thickness. Blood samples were collected every 10 days from the 11th month of gestation to 20 days post partum. Peripheral blood mononuclear cells were separated and tumour necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1α (IL-1α), -1β (ILβ), -2 (IL-2) and -6 (IL-6) gene expressions were performed by using reverse transcriptase PCR. TNF-α and IFN-γ expressions were affected by fatness group, as the sampling period influenced the expression of all cytokines with the exception of IFN-γ. The interaction between fatness group and sampling period tended to be significant (P < 0.10) only for IL-1β, TNF-α and IL-2. In H group, compared with L group, IL-1β and IL-2 significantly (P < 0.05) increased at parturition. TNF-α peripheral expression increased from parturition to reach the peak at +10 days (P < 0.05) only in H group. In conclusion, in normal BCS periparturient mares, small body fat thickness variations influence the peripheral cytokine expression, showing a possible role for cytokines in parturition and lactation, events strongly linked to adipose tissue availability.

Under- and over-nutrition during gestation may influence fetal hypothalamic development resulting in individuals predisposed to adverse health effects. This study examined fetuses from obese and control ewes to determine whether dam obesity alters hypothalamic expression of fetal appetite regulatory genes. A second objective was to contrast the expression of appetite regulatory genes in ewes that become the most obese to those that remained in moderate body condition on the same energy-rich diet. Multiparous, western white-faced ewes were weighed and individually fed 100% (control) or 150% (obese) of National Research Council requirements from day 60 before mating until day 75 of gestation. At day 75 of gestation, fetuses were collected and weighed. Hypothalamic tissue from fetal lambs and dams was collected and frozen for mRNA extraction. Dam obesity (P ⩾ 0.16), fetal sex (P ⩾ 0.44) or their interaction (P ⩾ 0.42) did not affect the relative expression of fetal hypothalamic regulators of appetite, including neuropeptide Y, agouti-related protein, pro-opiomelanocortin, cocaine- and amphetamine-regulated transcript and receptors for leptin. Maternal obesity at day 75 of gestation in ewes did not affect developmental mechanisms responsible for the expression of fetal appetite regulatory genes and would not be expected to predispose offspring to adult-onset obesity through disrupted appetite regulation at this developmental time point. In the ewe, appetite regulatory genes did not differ (P > 0.20) with ewe adiposity; however, expression of estrogen receptor α, but not β (P = 0.37), in the medial basal hypothalamus was greater (P = 0.04) in obese than in control ewes.

In the meat industry, the manipulation of fat deposition in cattle is of pivotal importance to improve production efficiency, carcass composition and ultimately meat quality. There is an increasing interest in the identification of key factors and molecular mechanisms responsible for the development of specific fat depots. This study aimed at elucidating the influence of breed and diet on adipose tissue membrane permeability and fluidity and their interplay on fat deposition in bovines. Two Portuguese autochthonous breeds, Alentejana and Barrosã, recognized as late- and early-maturing breeds, respectively, were chosen to examine the effects of breed and diet on fat deposition and on adipose membrane composition and permeability. Twenty-four male bovines from these breeds were fed on silage-based or concentrate-based diets for 11 months. Animals were slaughtered to determine their live slaughter and hot carcass weights, as well as weights of subcutaneous and visceral adipose depots. Mesenteric fat depots were excised and used to isolate adipocyte membrane vesicles where cholesterol content, fatty acid profile as well as permeability and fluidity were determined. Total accumulation of neither subcutaneous nor visceral fat was influenced by breed. In contrast, mesenteric and omental fat depots weights were higher in concentrate-fed bulls relative to silage-fed animals. Membrane fluidity and permeability to water and glycerol in mesenteric adipose tissue were found to be independent of breed and diet. Moreover, the deposition of cholesterol and unsaturated fatty acids, which may influence membrane properties, were unchanged among experimental groups. Adipose membrane lipids from the mesenteric fat depot of ruminants were rich in saturated fatty acids, and unaffected by polyunsaturated fatty acids dietary levels. Our results provide evidence against the involvement of cellular membrane permeability to glycerol on fat accumulation in mesenteric fat tissue of concentrate-fed bovines, which is consistent with the unchanged membrane lipid profile found among experimental groups.

Livestock farming has recently come under close scrutiny, in response especially to environmental issues. Farmers are encouraged to redesign their livestock farming systems in depth to improve their sustainability. Assuming that modelling can be a relevant tool to address such systemic changes, we sought to answer the following question: ‘How can livestock farming systems be modelled to help farmers redesign their whole farming systems?’ To this end, we made a literature review of the models of livestock farming systems published from 2000 to mid-2009 (n = 79). We used an analysis grid based on three considerations: (i) system definition, (ii) the intended use of the model and (iii) the way in which farmers’ decision-making processes were represented and how agricultural experts and farmers were involved in the modelling processes. Consistent rationales in approaches to supporting changes in livestock farming were identified in three different groups of models, covering 83% of the whole set. These could be defined according to (i) the way in which farmers’ decisions were represented and (ii) the model's type of contribution to supporting changes. The first type gathered models that dynamically simulated the system according to different management options; the farmers’ decision-making processes are assumed to consist in choosing certain values for management factors. Such models allow long-term simulations and endorse different disciplinary viewpoints, but the farmers are weakly involved in their design. Models of the second type can indicate the best combination of farm activities under given constraints, provided the farmers’ objectives are profit maximisation. However, when used to support redesigning processes, they address neither how to implement the optimal solution nor its long-term consequences. Models of the third type enable users to dynamically simulate different options for the farming system, the management of which is assumed to be planned according to the farmers’ general objectives. Although more comprehensive, these models do not easily integrate different disciplinary viewpoints and different subsystems, which limits their usefulness as support tools for redesigning processes. Finally, we concluded about what specific requirements should be for modelling approaches if farmers were to be supported in redesigning their whole livestock farming systems using models.

The incorporation of feed-use (FU) amino acids (AAs) in diets results in a reduced use of protein-rich ingredients such as soybean meal, recognized to have elevated contributions to environmental impacts. This study investigated whether the incorporation of l-lysine.HCl, l-threonine and FU-methionine reduces the environmental impacts of pig and broiler feeds using Life Cycle Assessment. The following impact categories were considered: climate change, eutrophication, acidification, terrestrial ecotoxicity, cumulative energy demand and land occupation. Several feeds were formulated either to minimize the cost of the formulation (with or without AA utilization), to maximize AA incorporation (i.e. the cost of AA was considered to be similar to that of soybean meal), or to minimize greenhouse gas emissions. For both pig and broiler feeds, calculations were made first using only cereals and soybean meal as main ingredients and then using cereals and several protein-rich ingredients (soybean meal, rapeseed meal and peas). In addition, these calculations were performed using two types of soybean meal (from Brazil, associated with recent deforestation or not). For broiler feeds, two types of maize (from France, irrigated, with mineral fertilization v. not irrigated, with animal manure fertilization) were also tested. Regarding the feeds formulated to minimize cost, incorporation of AA decreased the values for eutrophication, terrestrial ecotoxicity and cumulative energy demand of both pig and broiler feeds, regardless of the base ingredients. Reduction in climate change and acidification due to the incorporation of AA depended on the nature of the feed ingredients, with the effect of AA incorporation being greater when combined with ingredients with high impacts such as soybean meal associated with deforestation. Feeds formulated to maximize AA incorporation generally had a similar composition to those formulated to minimize cost, suggesting that the costs of AA were not the limiting factor in their incorporation. Feeds formulated to minimize greenhouse gas emissions had the lowest values for climate change and cumulative energy demand, but not for other impacts. Further research is needed to elucidate whether the incorporation of additional AA (tryptophan and valine) along with l-lysine, l-threonine and FU-methionine could decrease on the environmental impacts of pig and broiler feeds further.

Identification of breeding objective traits pertinent to specific production environments with the involvement of target beneficiaries is crucial to the success of a breed improvement program. A choice experiment was conducted in four locations representing different production systems and agro-ecologies that are habitat to four indigenous sheep breeds (Afar, Bonga, Horro and Menz) of Ethiopia with the objective of identifying farmers’/pastoralists’ preferences for sheep breeding traits. Following a synthesis of secondary information and diagnostic surveys, two communities per location consisting of 60 households each having at least four breeding ewes were identified. Producers’ priority attributes used in the choice sets were identified through in-depth production system studies conducted from December 2007 to March 2008. On the basis of prior information, four to seven attributes were used to design choice sets with different profiles in order to capture results that mimic real life of the different communities. The attributes and levels chosen for the sheep profile were as follows: body size (large/small), coat color (brown/white/black), tail type (good/bad) for both rams and ewes; horn (polled/horned) and libido (active/poor) for rams; and lambing interval (three lambings in 2 years/two lambings in 2 years time), mothering ability (good mother/bad mother), twinning rate (twin bearer/single bearer) and milk yield (two cups per milking/one cup per milking) for ewes. A fractional factorial design was implemented to construct the alternatives included in the choice sets. The design resulted in a randomized selection of 48 sheep profiles (24 sets) for both sexes, which were grouped into four blocks with six choice sets each. An individual respondent was presented with one of the four blocks to make his/her choices. Results indicate that producers’ trait preferences were heterogeneous except for body size in rams and mothering ability in ewes where nearly homogeneous preferences were investigated. In the pastoral production system, attention was given to coat color of both breeding rams and ewes, favoring brown and white colors over black. Ram libido influenced producers’ decisions in Bonga, Horro and Menz areas. The influence of milk yield and twinning on respondents’ decision making was high in Afar and Horro, respectively. Breeders in all areas attempt to combine production and reproduction traits as well as they can in order to maximize benefits from their sheep. The elicited measurable objective traits were used to design alternative community-based sheep breeding plans for the four indigenous sheep breeds in their production environments that have been implemented since.

The aim of the study was to examine the effect of a linseed diet on meat quality and on lipogenesis in rabbits. Twelve rabbits were fed a control or a linseed diet. There was no diet effect on growth, food consumption, carcass characteristics and meat ultimate pH and colour. Feeding the linseed diet increased the n-3 polyunsaturated fatty acids (PUFA) levels in perirenal and interscapular fats, in the Longissimus dorsi muscle and in the liver. The linseed diet produced lower linoleic acid/α-linolenic acid ratios in adipose tissues and in the Longissimus dorsi muscle, but not in the liver. Diet did not affect lipogenic enzyme activities in the Longissimus dorsi muscle, whereas the linseed diet decreased the lipogenic potential in perirenal and interscapular fats, and in the liver. Feeding rabbits with a high n-3 PUFA diet led to a decrease in the oxidative stability of perirenal fat and the Longissimus dorsi muscle, and to an inhibition of stearoyl-CoA-desaturase activity in liver and in adipose tissues, but not in muscle.

The ‘Organic’ product label guarantees a production process that avoids the use of synthetic fertilisers, pesticides and hormones and minimises recourse to pharmaceuticals or veterinary drugs; however, the product's quality remains an issue that needs to be addressed in response to consumer demand. Consequently, this study was conducted to compare the sensory and nutritional qualities of meat and carcasses from pasture-fed lambs reared organically (O) or conventionally (C). Mean lamb growth profile was kept similar between the two treatments to avoid confounding effects with lamb age or weight at slaughter. The experiment was conducted over 3 years (2005 to 2007) with 12 O and 12 C lambs each year. The O and C treatments differed in the level of on-pasture mineral N fertilisation inducing a higher proportion of white clover in the organic pasture than the conventional pasture. Lambs were slaughtered when they attained a fat class of 2 to 3, and carcass and meat quality were evaluated. Lambs were slaughtered at an average weight and age of 35.3 kg and 156 days in the O treatment, respectively, and 35.2 kg and 155 days in the C treatment, respectively. Sensory evaluation indicated that loin chops from the O treatment had a higher level of abnormal fat odour compared with the C treatment. Carcasses from the O treatment had a softer subcutaneous fat one among 3 years (2007) compared to the C treatment. These results are probably due to a higher proportion of white clover in the diet. Organically reared lambs did offer the slight advantage of muscle fatty acid containing a higher level of stearic acid, which may have positive effects in the prevention of cardiovascular disease in humans. This may be the result of a higher rumen bio-hydrogenation of C18:3n-3 due to differences in the botanical composition between the O and the C pasture. Production system had no effect on the colour characteristics of the meat and subcutaneous fat, except lightness of subcutaneous dorsal fat, which was slightly higher in the O lambs. There were no differences between O and C lambs in terms of colour stability and lipid oxidation of the meat during the 6-day refrigerated storage under gas-permeable film.

To evaluate meat quality of beef with different α-tocopherol tissue levels, 55 feedlot steers were fed a barley-based finisher diet with four vitamin E supplementation levels (0, 350, 700 and 1400 IU dl-α-tocopheryl acetate/animal per day) for 120 days. Although the increase in oxidation levels overtime was much smaller (P < 0.001) in the high-medium and high groups, α-tocopherol tissue levels did not affect (P > 0.05) pH, proximate analysis, drip and cooking losses, and shear force of steaks. No effect of α-tocopherol tissue levels was found in retail evaluation of steaks after a short ageing time of 6 days, but with 21 days of ageing, a delay in formation of metmyoglobin (P = 0.008) was observed in steaks with higher tissue levels of α-tocopherol. Similar results were found for ground beef (25% fat) prepared from 6-day aged meat. Thus, higher α-tocopherol tissue levels protect ground beef and long-aged steaks from discolouration and lipid oxidation.