Lebret B
INRA, UMR 1079, Livestock Production Systems, Animal and Human Nutrition, F-35000 Rennes, France.
Animal. 2008 Oct;2(10):1548-58. doi: 10.1017/S1751731108002796.
Animal growth performance and quality of pork depend on the interactive effects of pig genotype, rearing conditions, pre-slaughter handling, and carcass and meat processing. This paper focuses on the effects of feeding and rearing systems (feeding level and diet composition, housing, production system, etc.) on growth performance, carcass composition, and eating and technological qualities of pork. The feeding level and protein : energy ratio can be used to manipulate growth rate or composition of weight gain. Restricted feed allowance strongly reduces growth rate and carcass fatness and also intramuscular fat (IMF) level, resulting in decreased meat tenderness or juiciness. Expression of compensatory growth due to restricted followed by ad libitum feeding modifies the composition of weight gain at both carcass and muscle levels, and may improve meat tenderness due to higher in vivo protein turnover. Decreasing the protein : energy ratio of the diet actually increases IMF and improves eating quality, but gives fatter carcasses. In contrast, a progressive reduction in the protein : energy ratio leads to similar carcass composition at slaughter but with higher IMF. Technological meat traits (pH1, pHu, colour, drip loss) are generally not affected by the level or protein : energy in feed. Modification of fatty acid composition and antioxidant level in meat can be obtained through diet supplementations (e.g. vegetable sources with high n-3 fatty acids), thereby improving the nutritional quality of pork. Influences of pig rearing system on animal performance, carcass and meat traits result from interactive effects of housing (floor type, space allowance, ambient temperature, physical activity), feeding level and genotype in specific production systems. Indoor enrichment (more space, straw bedding) generally increases growth rate and carcass fatness, and may improve meat juiciness or flavour through higher IMF. Outdoor rearing and organic production system have various effects on growth rate and carcass fatness, depending on climatic conditions and feed allowance. Influence on meat quality is also controversial: higher drip and lower pHu and tenderness have been reported, whereas some studies show improved meat juiciness with outdoor rearing. Discrepancies are likely due to differences between studies in rearing conditions and physiological responses of pigs to pre-slaughter handling. Specific production systems of the Mediterranean area based on local breeds (low growth rate, high adiposity) and free-range finishing (pasture, forests), which allows pig to express their genetic potential for IMF deposition, clearly demonstrate the positive effects of genotype × rearing system interactions on the quality of pork and pork products.
猪的生长性能和猪肉品质取决于猪的基因型、饲养条件、屠宰前处理以及胴体和肉类加工之间的相互作用。本文重点关注饲养和养殖系统（饲养水平和日粮组成、猪舍、生产系统等）对猪生长性能、胴体组成以及猪肉食用品质和加工品质的影响。饲养水平和蛋白质:能量比可用于调控生长速度或增重组成。限饲会显著降低生长速度、胴体脂肪含量以及肌内脂肪（IMF）水平，导致肉的嫩度或多汁性下降。限饲后再自由采食引起的补偿性生长会改变胴体和肌肉水平的增重组成，并且由于体内蛋白质周转率较高，可能会改善肉的嫩度。降低日粮的蛋白质:能量比实际上会增加IMF并改善食用品质，但会使胴体更肥。相反，逐步降低蛋白质:能量比会使屠宰时的胴体组成相似，但IMF含量更高。肉的加工特性（pH1、pHu、颜色、滴水损失）通常不受饲料中蛋白质水平或蛋白质:能量比的影响。通过日粮添加（例如富含n-3脂肪酸的植物来源）可以改变肉中的脂肪酸组成和抗氧化剂水平，从而提高猪肉的营养品质。猪养殖系统对动物性能、胴体和肉品质的影响源于特定生产系统中猪舍（地面类型、空间、环境温度、体力活动）、饲养水平和基因型之间的相互作用。室内丰富环境（更大空间、稻草垫料）通常会提高生长速度和胴体脂肪含量，并且可能通过增加IMF来改善肉的多汁性或风味。户外饲养和有机生产系统对生长速度和胴体脂肪含量有不同影响，这取决于气候条件和采食量。对肉质的影响也存在争议：有报道称滴水损失增加、pHu降低和嫩度下降，而一些研究表明户外饲养可改善肉的多汁性。差异可能是由于不同研究的饲养条件以及猪对屠宰前处理的生理反应不同所致。地中海地区基于当地品种（生长速度慢、脂肪含量高）和自由放养育肥（牧场、森林）的特定生产系统，能让猪充分发挥其IMF沉积的遗传潜力，清楚地证明了基因型×养殖系统相互作用对猪肉及猪肉产品品质的积极影响。
