Sørensen M T, Oksbjerg N, Agergaard N, Petersen J S
Danish Institute of Animal Science, Research Centre Foulum, Tjele, Denmark.
Comp Biochem Physiol A Physiol. 1996 Feb;113(2):91-6. doi: 10.1016/0300-9629(95)02038-1.
Two experiments were conducted to examine the effect of porcine growth hormone (pGH) on performance, carcase composition, muscle and fat deposition rates, muscle fibre characteristics, and fat cell volume in pigs. In the first experiment, ten pairs of littermates were treated with vehicle (saline buffer) or 80 micrograms pGH per kg live weight per day for 42 days starting at 50 kg live weight. In the second experiment, twelve pairs of littermates were untreated or treated with 3 mg pGH per day from approximately 56 kg live weight to slaughter at approximately 103 kg live weight. All pigs were fed ad libitum. In Experiments 1 and 2, respectively, feed intake decreased (10 and 11%) and the feed/grain ratio improved (8 and 13%), while daily gain was unaltered. There was an increase in deposition rates of muscle (11 and 22%), skin (27 and 23%), and bone (15% in both), and a decrease in deposition rates of intermuscular (48 and 24%) and subcutaneous (82 and 50%) fat. This resulted in a change in carcase composition towards more muscle (5 and 9%), bone (6 and 4%), and skin (18 and 12%), and less intermuscular (30 and 16%) and subcutaneous fat (51 and 32%). The increased muscle mass was due to enhanced hypertrophy of all muscle fibre types, while pGH did not affect the frequency of the different muscle fibre types. The reduction in subcutaneous fat was reflected in a similar reduction in fat cell volume. In contrast to the majority of pigs used in pGH experiments, the genotype used in the present experiments did not respond with respect to daily gain following pGH treatment. Furthermore, the increase in muscle deposition was rather low compared to results reported in pigs of other genotypes. These data together with published data on the cross-sectional area of muscle fibres indicate that genotypes with relatively large muscle fibres are less responsive to pGH treatment than genotypes with relatively small muscle fibres.
进行了两项实验，以研究猪生长激素（pGH）对猪的生产性能、胴体组成、肌肉和脂肪沉积率、肌纤维特性以及脂肪细胞体积的影响。在第一项实验中，从50千克体重开始，10对同窝仔猪分别用赋形剂（生理盐水缓冲液）或每天每千克体重80微克pGH处理42天。在第二项实验中，12对同窝仔猪不进行处理或从大约56千克体重开始至大约103千克体重屠宰时每天用3毫克pGH处理。所有猪均自由采食。在实验1和实验2中，采食量分别下降了10%和11%，饲料/谷物比分别提高了8%和13%，而日增重未改变。肌肉（分别为11%和22%）、皮肤（分别为27%和23%）和骨骼（均为15%）的沉积率增加，而肌间（分别为48%和24%）和皮下（分别为82%和50%）脂肪的沉积率下降。这导致胴体组成发生变化，肌肉（分别增加5%和9%）、骨骼（分别增加6%和4%）和皮肤（分别增加18%和12%）增多，肌间（分别减少30%和16%）和皮下脂肪（分别减少51%和32%）减少。肌肉量增加是由于所有肌纤维类型的肥大增强，而pGH不影响不同肌纤维类型的频率。皮下脂肪的减少反映在脂肪细胞体积的类似减少上。与大多数用于pGH实验的猪不同，本实验中使用的基因型在pGH处理后对日增重没有反应。此外，与其他基因型猪的报道结果相比，肌肉沉积的增加相当低。这些数据以及已发表的关于肌纤维横截面积的数据表明，肌纤维相对较大的基因型对pGH处理的反应不如肌纤维相对较小的基因型。
