Effects of crossbreeding on slaughter traits and breast muscle chemical composition in chinese chickens

We investigated the effects of crossbreeding on slaughter traits and the chemical composition of chicken breast muscle. Trials were conducted using 120 broilers from four lines: Xiao-Shan chicken (XS), Xian-Ju chicken (XJ), Xiao-Shan chicken&#9794;&#9794; × Xian-Ju chicken&#9792;&#9792; (Zhenan 1, ZNY1) and Xiao-Shan chicken&#9794;&#9794; × (Guang-Xi Yellow chicken&#9794;&#9794;×Xian-Ju chicken&#9792;&#9792;) &#9792;&#9792; (Zhenan 2, ZNY2). The birds were slaughtered at 120 days of age and the slaughter traits were measured. Breast muscles were sampled to determine chemical composition. The slaughter traits of hybrid chickens were improved. Both hybrid strains had higher intramuscular fat (IMF) and inosine-5'-monophosphate (inosinic acid, IMP). Concentrations of monounsaturated fatty acids (MUFA) in breast muscles from the two hybrids were significantly higher than in the other two breeds (p < 0.05). The concentration of polyunsaturated fatty acids (PUFA) in the breast muscles of the two hybrids was significantly lower than in the other two breeds (p < 0.05). ZNY2 had significantly lower (p < 0.05) concentrations of myristic acid (C14:0). The breast muscle of ZNY1 had significantly higher palmitic acid (C16:0) concentrations than XS, XJ, or ZNY2 (p < 0.05). The concentrations of oleic acid (C18:1) and eicosapentaenoic acid (C20:5n-3, EPA) in breast muscle from the two hybrid lines were significantly higher than the other two breeds (p < 0.05). Breast muscles from XS and XJ chickens contained significantly higher docosahexenoic acid (C22:6n-3, DHA) than the two hybrid lines (p < 0.05). The XS and XJ chickens had lower n-6/n-3 ratios than the two hybrids (p < 0.05). Breast muscles from ZNY1 and ZNY2 contained higher concentrations of essential amino acids (p < 0.05), total amino acids (p < 0.05), and some individual amino acids (p < 0.05). In conclusion, crossbreeding improved the slaughter traits of chickens and increased intramuscular fat and inosinic acid content in breast muscle. The fatty acid and amino acid compositions of breast muscles were also improved by crossbreeding

A review of fatty acid profiles and antioxidant content in grass-fed and grain-fed beef

<p>Abstract</p> <p>Growing consumer interest in grass-fed beef products has raised a number of questions with regard to the perceived differences in nutritional quality between grass-fed and grain-fed cattle. Research spanning three decades suggests that grass-based diets can significantly improve the fatty acid (FA) composition and antioxidant content of beef, albeit with variable impacts on overall palatability. Grass-based diets have been shown to enhance total conjugated linoleic acid (CLA) (C18:2) isomers, <it>trans </it>vaccenic acid (TVA) (C18:1 t11), a precursor to CLA, and omega-3 (n-3) FAs on a g/g fat basis. While the overall concentration of total SFAs is not different between feeding regimens, grass-finished beef tends toward a higher proportion of cholesterol neutral stearic FA (C18:0), and less cholesterol-elevating SFAs such as myristic (C14:0) and palmitic (C16:0) FAs. Several studies suggest that grass-based diets elevate precursors for Vitamin A and E, as well as cancer fighting antioxidants such as glutathione (GT) and superoxide dismutase (SOD) activity as compared to grain-fed contemporaries. Fat conscious consumers will also prefer the overall lower fat content of a grass-fed beef product. However, consumers should be aware that the differences in FA content will also give grass-fed beef a distinct grass flavor and unique cooking qualities that should be considered when making the transition from grain-fed beef. In addition, the fat from grass-finished beef may have a yellowish appearance from the elevated carotenoid content (precursor to Vitamin A). It is also noted that grain-fed beef consumers may achieve similar intakes of both n-3 and CLA through the consumption of higher fat grain-fed portions.</p