Goat meat is considered healthy because of its low fat content, but it is often rather tough. Tenderness is the most important attribute of quality during meat consumption and there is scarce information about the expression of genes involved in the meat tenderization process in goats. The aim of this trial was to assess certain meat quality traits and the expression, at the messenger RNA (mRNA) and protein levels, of specific genes involved in the tenderization process of the longissimus lumborum (LL) in young male goats (Capra hircus) at different ages. Samples of LL were collected at slaughter from 32 Alpine goats that were divided into three categories: 9 suckling kids (Sk) at 5.4±0.15 weeks of age, 16 chevons (Ch) at 17.1±0.55 weeks of age and 7 post-puberal goats (Pu) at 34.3±2.5 weeks of age. Animal and carcass variables (live weight gain, live weight, carcass weight and fat deposits) and quality traits of meat (lipid content, ultimate pH, color parameters, cooking loss and shear force) were determined. The mRNA abundances of calpain-1 (Capn1), calpain-2 (Capn2), calpastatin (Cast), caspase 3 (Casp3), caspase 9 (Casp9), αB-crystallin (Cryab), heat shock protein 27 (Hsp27), heat shock protein 40 (Hsp40) and heat shock protein 70 (Hsp70) were detected by quantitative PCR. Capn1, Cast, Cryab and Hsp27 protein expression was investigated by ELISA. The Sk group had the leanest carcasses. The meat of the Pu group was the darkest (P<0.05) and the toughest (P<0.05). The redness of meat increased with the age of the goats. The Sk group showed lower mRNA abundances for the Capn2/Cast ratio, Casp3, Cryab, Hsp27, Hsp40 and Hsp70 than the Pu group (P<0.05). Intermediate values were found for the Ch group. Similar results were highlighted for the protein expression of Cryab and Hsp27. The experiment acknowledged a differentiation of the experimental groups based on performance, carcass and meat characteristics, and the genes considered. Moreover, Sk and Pu groups, characterized by a different tenderness of their meat, were clearly discriminated by a different expression of the Hsp.

The objective of this trial was to determine the effect of breed and long-term dietary linseed addition on composition of fatty acids and expression of some genes involved in the lipid metabolism within subcutaneous (s.c.) adipose tissue of young bulls. Italian Simmental and Holstein bulls (n = 16/breed) were fed a corn silage–grass hay diet with or without 8% (DM basis) whole ground linseed. Inclusion of linseed, rich in α-linoleic acid (C18:3n-3), increased (P < 0.05) the proportions of linolelaidic (C18:2n-6trans), γ-linolenic (C18:3n-6), C18:3n-3, and rumenic (cis9,trans11 conjugated linoleic acid) acids, as well as total n-3 fatty acid, total PUFA, and PUFA:SFA, but decreased (P < 0.05) weight percentages of myristic (C14:0), pentadecanoic (C15:0), palmitic (C16:0), palmitelaidic (C16:1n-9trans), and margaric (C17:0) acids, along with n-6:n-3, in the s.c. fat of young bulls. Even though PUFA were similar (P ≥ 0.23) between bull breeds, s.c. fat from Holstein bulls had greater (P < 0.05) proportions of tridecylic (C13:0), myristoleic (C14:1) and palmitoleic (C16:1n-9cis) acids and a lower (P < 0.05) proportion of margaric (C17:0) acid than s.c. fat from Simmental bulls. Feeding linseed decreased (P < 0.05) the expression of stearoyl CoA desaturase (SCD) and the lipoprotein lipase (LPL) gene without affecting (P ≥ 0.19) fatty acid synthase (FASN), leptin (LEP), and PPARγ2 mRNA in the s.c. fat of bulls; however, there was no effect of bull breed (P ≥ 0.11) or interactive effect of breed and linseed (P ≥ 0.23) on gene expression. Expression of PPARγ2 was positively correlated with SCD (r = 0.454; P = 0.01), LEP (r = 0.500; P < 0.01), and LPL (r = 0.531; P < 0.01) mRNA, indicating that PPARγ2 increases the expression of genes involved in lipogenesis. Copyright © 2013. American Society of Animal Science .