Bender J M, See M T, Hanson D J, Lawrence T E, Cassady J P
Department of Animal Science, North Carolina State University, Raleigh, 27695-7621, USA.
J Anim Sci. 2006 Jun;84(6):1331-7. doi: 10.2527/2006.8461331x.
The objective of this project was to characterize changes in growth, carcass yield, and meat quality traits in castrates and gilts in response to divergent selection for testosterone production. In generation 21, endogenous testosterone concentrations in Duroc boars of the high (HTL) and low (LTL) testosterone lines averaged 49.0 and 27.8 ng/mL (P < 0.01), respectively. Eight LTL and 10 HTL boars were used to sire 29 LTL and 33 HTL litters. To remove the effects of inbreeding, these same boars were mated to females of a Large White x Landrace composite (WC) to generate 11 WC by LTL litters (WLT) and 23 WC by HTL litters (WHT). Castrates and gilts were then allotted to LTL (n = 53), HTL (n = 61), WLT (n = 102), and WHT (n = 101) for testing. Growth and carcass traits analyzed included days to 114 kg (D114), ADG, backfat adjusted to 114 kg (ABF), LM area adjusted to 114 kg and predicted percent lean (PPL). Fat-O-Meater data collected were adjusted fat depth (AFD), adjusted loin depth, and percent lean. Meat quality traits characterized at 24 h postmortem included marbling score, percent lipid, pH, drip loss, color score, and Minolta L*, a*, and b*. Data were analyzed with a mixed model including fixed effects of line, mating type (purebred or crossbred), sex, and the random effect of sire nested within line. All possible interactions among fixed effects were tested. The HTL had fewer D114 (P < 0.05), greater ADG (P < 0.01), greater ABF (P < 0.01), and lower PPL (P < 0.01) than LTL. The WHT and WLT did not differ for D114, ADG, or ABF. The WHT had smaller LM area adjusted to 114 kg (P < 0.05) and greater drip loss (P < 0.05) than WLT. The WLT had lower adjusted loin depth (P < 0.05) than LTL and HTL. The LTL and HTL had greater subjective scores for marbling (P < 0.05) compared with WLT and WHT. The least squares mean for percent lipid for HTL and LTL was 4.00. The WHT had greater means for L*, a*, and b* (P < 0.05) than WLT. Pigs selected for increased testosterone production grew faster and produced fatter carcasses than pigs selected for decreased testosterone. Changes in growth, carcass yield, and meat quality traits were detected in castrates and gilts in response to divergent selection for testosterone production.
本项目的目的是研究去势公猪和后备母猪在针对睾酮生成进行不同选择后，其生长性能、胴体产量和肉质性状的变化。在第21代时，高睾酮系（HTL）和低睾酮系（LTL）杜洛克公猪的内源性睾酮浓度平均分别为49.0和27.8 ng/mL（P < 0.01）。选用8头LTL公猪和10头HTL公猪，分别与29窝LTL仔猪和33窝HTL仔猪的母猪配种。为消除近亲繁殖的影响，这些公猪与大白猪×长白猪杂交组合（WC）的母猪交配，产生了11窝LTL与WC的杂交仔猪（WLT）和23窝HTL与WC的杂交仔猪（WHT）。然后将去势公猪和后备母猪分配到LTL组（n = 53）、HTL组（n = 61）、WLT组（n = 102）和WHT组（n = 101）进行测试。分析的生长和胴体性状包括达114 kg体重的天数（D114）、平均日增重（ADG）、校正至114 kg体重的背膘厚（ABF）、校正至114 kg体重的眼肌面积以及预测瘦肉率（PPL）。收集的Fat - O - Meater数据包括调整后的脂肪深度（AFD）、调整后的腰荐部深度和瘦肉率。宰后24 h测定的肉质性状包括大理石花纹评分、脂肪百分比、pH值、滴水损失、颜色评分以及美能达L*、a和b值。数据采用混合模型进行分析，固定效应包括品系、交配类型（纯种或杂交）、性别，随机效应为品系内的父系。对固定效应之间的所有可能交互作用进行了检验。与LTL相比，HTL的D114天数更少（P < 0.05），ADG更高（P < 0.01），ABF更厚（P < 0.01），PPL更低（P < 0.01）。WHT和WLT在D114、ADG或ABF方面没有差异。与WLT相比，WHT校正至114 kg体重的眼肌面积更小（P < 0.05），滴水损失更大（P < 0.05）。WLT的调整后腰荐部深度低于LTL和HTL（P < 0.05）。与WLT和WHT相比，LTL和HTL的大理石花纹主观评分更高（P < 0.05）。HTL和LTL的脂肪百分比最小二乘均值为4.00。与WLT相比，WHT的L*、a和b均值更高（P < 0.05）。选择用于提高睾酮生成的猪比选择用于降低睾酮生成的猪生长更快，胴体更肥。在去势公猪和后备母猪中，针对睾酮生成的不同选择导致了生长、胴体产量和肉质性状的变化。
