Averette Gatlin L, See M T, Hansen J A, Odle J
Department of Animal Science, North Carolina State University, Raleigh 27695-7621, USA.
J Anim Sci. 2003 Aug;81(8):1989-97. doi: 10.2527/2003.8181989x.
Pork quality is influenced by nutrition, genetics, management, and pork-processing procedures. Pigs of lean genotype fed diets high in unsaturated fat may have thinner, lower-quality bellies with a soft fat composition. Therefore, we investigated the effects of supplementing 5% choice white grease that had been chemically hydrogenated to iodine values of 80, 60, 40, or 20 on pork quality. Diets were fed to barrows and gilts of two genotypes (NPD [Ham-line x Manor hybrid] and PIC [406, 419, or 420 x C22]; n = 240) in a 4 x 2 x 2 factorial design. Pigs (76.8 kg of mean initial weight) were placed on test at a common age and were fed dietary treatments for 52 d. Pigs of PIC genotype were heavier at trial initiation, had higher feed intake and feed conversion ratio (F/G; P < 0.05), and greater backfat (26.3 vs. 24.0 mm; P < 0.001) and loin depth (59.0 vs. 55.3 mm; P < 0.001) compared with the NPD genotype pigs. As the iodine value of dietary fat was reduced, belly thickness increased (P < 0.05) and length decreased linearly (P < 0.05). Congruently, belly fat iodine value decreased from 73.9 to 67.4 (linear effect; P < 0.001) and belly fat C18:2 concentration declined from 20.6 to 16.3% (linear and quadratic effect; P < 0.001). The belly mono- and polyunsaturated fat ratio increased 29% as diet iodine value declined from 80 to 20 (linear and quadratic effect; P < 0.001). Further, there was a linear increase (P < 0.001) in saturated fatty acid concentration of belly fat (C14:0, C16:0, and C18:0) as dietary fat iodine value declined. Quadratic (P < 0.005) effects were detected in the level of C18:1trans as iodine value decreased from 80 to 20, paralleling dietary content. Dietary fat iodine value did not affect fat digestibility, ADFI, or F/G. Pork belly quality was improved as defined by reduced iodine value, C18:2 content, increased saturated fatty acid content, increased thickness, and decreased length as dietary iodine value decreased. Results indicate that reduction of dietary fat iodine value by chemical hydrogenation has the desirable effect of improving pork quality and does not alter growth performance.
猪肉品质受营养、遗传、管理及猪肉加工程序的影响。饲喂高不饱和脂肪日粮的瘦肉型基因型猪，其腹部脂肪可能更薄、品质更低，且脂肪质地较软。因此，我们研究了添加5%经化学氢化处理使其碘值分别为80、60、40或20的精选白油脂对猪肉品质的影响。采用4×2×2析因设计，将日粮喂给两种基因型（NPD[汉普夏系×庄园杂交种]和PIC[406、419或420×C22]；n = 240）的公猪和母猪。猪（平均初始体重76.8 kg）在相同年龄开始试验，并接受日粮处理52天。与NPD基因型猪相比，PIC基因型猪在试验开始时体重更重，采食量和饲料转化率（F/G；P < 0.05）更高，背膘更厚（26.3对24.0 mm；P < 0.001）， loin深度更大（59.0对55.3 mm；P < 0.001）。随着日粮脂肪碘值降低，腹部厚度增加（P < 0.05），长度呈线性下降（P < 0.05）。同样，腹部脂肪碘值从73.9降至67.4（线性效应；P < 0.001），腹部脂肪C18:2浓度从20.6%降至16.3%（线性和二次效应；P < 0.001）。当日粮碘值从80降至20时，腹部单不饱和脂肪酸和多不饱和脂肪酸比例增加29%（线性和二次效应；P < 0.001）。此外，随着日粮脂肪碘值降低，腹部脂肪饱和脂肪酸（C14:0、C16:0和C18:0）浓度呈线性增加（P < 0.001）。随着碘值从80降至20，反式C18:1水平检测到二次效应（P < 0.005），与日粮含量平行。日粮脂肪碘值不影响脂肪消化率、平均日采食量或F/G。随着日粮碘值降低，通过降低碘值、C18:2含量、增加饱和脂肪酸含量、增加厚度和减小长度来定义的猪肚品质得到改善。结果表明，通过化学氢化降低日粮脂肪碘值对改善猪肉品质具有理想效果，且不改变生长性能。
