Animal Research 

About: Animal Research is an academic journal. The journal publishes majorly in the area(s): Rumen & Grazing. It has an ISSN identifier of 1627-3583. Over the lifetime, 262 publications have been published receiving 9621 citations.

Meat fatty acid composition as affected by fatness and genetic factors: a review

Abstract: Meat fatty acid composition is influenced by genetic factors, although to a lower extent than dietary factors. The species is the major source of variation in fatty acid composition with ruminant meats being more saturated as a result of biohydrogenation in the rumen compared to the meat of monogastric animals. The level of fatness also has an effect on the meat fatty acid composition. The contents of saturated (SFA) and monounsaturated (MUFA) fatty acids increase faster with increasing fatness than does the content of PUFA, resulting in a decrease in the relative proportion of PUFA and consequently in the polyunsaturated/saturated fatty acids (P/S) ratio. The dilution of phospholipids with triacylglycerols and the distinct differences in fatty acid composition of these fractions explain the decrease in the P/S ratio with increasing fatness. An exponential model was fitted to the literature data for beef and showed a sharply increasing P/S ratio at low levels of intramuscular fat. Lowering the fat level of beef is thus more efficient in increasing the P/S ratio than dietary interventions. For pork, the intramuscular fat level also affects the P/S ratio, but nutrition will have a larger impact. The fat level also influences the n-6/n-3 PUFA ratio, due to the difference of this ratio in polar and neutral lipids. However, these effects are much smaller than the effects that can be achieved by dietary means. Differences in fatty acid composition between breeds and genotypes can be largely explained by differences in fatness. However, after correction for fat level, breed or genotype differences in the MUFA/SFA ratio and in the longer chain C20 and C22 PUFA metabolism have been reported, reflecting the possible genetic differences in fatty acid metabolism. Breed differences in meat conjugated linoleic acid (CLA) content have not yet been reported, but the c9t11CLA content in meat is positively related to the total fat content. Heritabilities and genetic correlations for the proportion of certain fatty acids have been estimated in a few studies, and correspond to the observations at the phenotypic level in relation to the intramuscular fat level. Although there is potential for genetic change, incorporating fatty acid composition as a goal in classical breeding programs does not seem worthwhile at the present. Enzyme activities have been measured in a few studies, but are not able to explain between-animal variation in fatty acid composition. Biochemical and molecular genetic studies should be encouraged to unravel the mechanisms responsible for differences in the metabolism and incorporation of specific fatty acids in meat. fatty acids / meat / genetics / P/S ratio

Effects of grass feeding systems on ruminant meat colour and flavour. A review

Abstract: Grass feeding has been reported to affect several meat quality characteristics, in particular colour and flavour. In this paper we have reviewed some differences in meat colour and flavour between ruminants fed concentrates and animals allowed to graze pasture. The possible factors influ- encing the differences have been also examined. We have examined a total of 35 experiments which report the effect of pasture vs concentrate finishing systems on beef meat colour. Meat from cattle raised on pasture is reported to be darker than meat from animals raised on concentrates if measured by objec- tive (P < 0.001) as well as subjective ( P < 0.05) methods. Several factors, not a specific one are responsible for this difference, variations in ultimate-pH and in intramuscular fat content between ani- mals finished at pasture and those finished on concentrates, seem to play a major role. Diet also affects meat flavour in both sheep and cattle but the components involved seem to be different. In sheep pastoral flavour is mostly determined by the branched-chain fatty acids and 3-methylindole (ska- tole). An important role seems to be played also by some products of oxidation of linolenic acid and its derivates. In cattle the role of skatole seems to be less important than sheep because of the lack of the branched-chain fatty acids. The pastoral flavour seems to be mostly determined by products of oxidation of linolenic acid and its derivates which derives substantially from grass. grass feeding / meat colour / meat flavour / ruminants

The relationship of temperature-humidity index with milk production of dairy cows in a Mediterranean climate

Abstract: Two experiments were conducted using lactating Friesian-Holstein cows to measure the effects of heat stress, using temperature-humidity index (THI), on milk production, milk composition and dry matter intake (DMI) under the Mediterranean climate. These trials were carried out in two pe- riods differing in average THI values (68 ± 3.75 vs. 78 ± 3.23 for the spring and summer periods, re- spectively). Daily THI was negatively correlated to milk yield (r = -0.76) and feed intake (r = -0.24). When the THI value increased from 68 to 78, milk production decreased by 21% and DMI by 9.6%. Milk yield decreased by 0.41 kg per cow per day for each point increase in the THI values above 69. Milk fat (3.24 vs. 3.58%) and milk protein (2.88 vs. 2.96%) were lower for the summer group. THI was positively correlated to respiration rate (RR) (r = 0.89), heart rate (HR) (r = 0.88), rectal tempera- ture (RT) (r = 0.85) and cortisol (0.31), and negatively with free thyroxin (-0.43). As the THI values increased from 68 to 78, RT increased by 0.5 o C, HR by 6 beats, and RR by 5 inspirations per min. The average concentration of cortisol increased from 21.75 to 23.5 nmol·L -1 (P > 0.05), while that of free thyroxin decreased from 15.5 to 14.5 pmol·L -1 ,( P > 0.05). Summer heat stress reduced milk yield and DMI, altered milk composition and affected the physiological functions of confined lactating Hol- stein cows managed under Mediterranean climatic conditions. dairy cow / temperature-humidity index / milk production / intake / physiology

Mycotoxins in feeds and their fate in animals: a review

Abstract: Mycotoxins are secondary metabolites secreted by moulds, mostly belonging to the three genera Aspergillus, Penicillium and Fusarium. They are produced in cereal grains as well as for- ages before, during and after harvest, in various environmental conditions. Due to the diversity of their toxic effects and their synergetic properties, mycotoxins are considered as risky to the consum- ers of contaminated foods. Mycotoxin metabolism is complex and involves pathways of bioactivation and detoxification in both humans and animals. Detoxification occurs via biotransformation mediated by enzymes in the host cells and in the digestive microbial flora. Some of the toxins or their metabolites may become fixed in animal or human tissues. However, most are elim- inated in the urine, faeces and milk. In animals, toxicity is generally revealed as chronic minor trou- bles and only rarely causes death. The presence of mycotoxins in feeds may decrease feed intake and affect animal performance. In addition, the possible presence of toxic residues in edible animal prod- ucts (milk, meat, offal), may have some detrimental effects on human health. Maximum acceptable doses in feeds and milk have been set for certain mycotoxins by international authorities. The poten- tial risks of mycotoxins may be controlled by checking plant material for fungal contamination, by improving methods of cultivation, harvest and storage, by eliminating or diluting toxins from the con- taminated food or feeds, and by using adsorbents to reduce the bioavailability of toxins in the diges- tive tracts of animals. These measures will be assessed in the present paper. mycotoxins / feeds / ruminants / detoxification / rumen microbes

Gut function and dysfunction in young pigs: physiology

Abstract: The post-weaning period in pigs is characterized by an immediate but transient drop in feed intake resulting in severe undernutrition and growth check. This in turn affects various aspects of small intestinal architecture and function leading to gut-associated disorders and often diarrhea. Among these, villus atrophy and digestive enzyme activity depression have been documented. More recent investigations clearly demonstrate early signs of local inflammation including immune cell infiltration and increased pro-inflammatory cytokine gene expression, signs of cytoprotection through up-regulation of so-called heat shock proteins, indications of tissue alterations by proteases (stromelysin) and finally epithelial functional disorders in mineral absorption/secretion and perme- ability. This is followed by a regenerative phase, probably stimulated by feed intake resumption, resulting in down-regulation of many intestinal indicators. However, some of them then display new spatio-temporal adult-type adaptive patterns of maturation. A limited number of substances, partic- ularly nitrogenous compounds and complex preparations of animal origin (colostrum, plasma) have proven to be successful, at least partly, in minimizing post-weaning intestinal disturbances. Thus further research in intestinal physiology, in association with microbiology and immunology, is war- ranted to strengthen our understanding of the mechanisms of gut disorders in order to provide a better rational basis for designing suitable alternatives to in-feed antibiotics for pigs.