棉籽粕膨化前后品质变化及对生长育肥猪生长性能、血清生化指标及营养物质表观消化率的影响

Quality Changes of Cottonseed Meal Before and After Expansion and Their Effects on Growth Performance,Serum Biochemical Indices and Nutrient Apparent Digestibility of Growing-Finishing Pigs

本试验旨在研究湿法挤压膨化加工对棉籽粕中营养物质、游离棉酚含量的影响,以及膨化棉籽粕对生长育肥猪生长性能、血清生化指标及营养物质表观消化率的影响。首先,采用牧羊56×2挤压膨化机和前期优化后的加工参数组合对棉籽粕进行膨化,对比测定棉籽粕和膨化棉籽粕的营养物质和游离棉酚含量的变化。然后,以棉籽粕和膨化棉籽粕为主要试验材料,选取80头体重为(28.78±3.09)kg的杜×长×大三元杂交猪为试验动物,随机分为5个组,每组4个重复,每个重复4头猪(公母各占1/2)。对照组饲喂全玉米-豆粕型基础饲粮,试验1组饲喂添加普通棉籽粕(生长期添加5%普通棉籽粕,育肥期添加10%普通棉籽粕)的饲粮,试验2组、试验3组、试验4组分别饲喂添加膨化棉籽粕(生长期分别添加5%、10%和15%膨化棉籽粕,育肥期分别添加10%、15%和20%膨化棉籽粕)的饲粮,各组饲粮中代谢能和粗蛋白质等营养水平均调配均衡。试验期13周(生长期6周,育肥期7周)。结果表明:1)挤压膨化处理对棉籽粕营养物质含量无明显影响,膨化棉籽粕总氨基酸含量和各个必需氨基酸含量略有升高,游离棉酚含量降低了87.85%。2)生长期,饲粮中添加5%膨化棉籽粕与相同含量的普通棉籽粕相比可提高生长猪的平均日采食量和平均日增重(P>0.05),显著降低料重比(P<0.05),并显著提高粗蛋白质、干物质、粗脂肪和部分氨基酸表观消化率(P<0.05);饲粮中添加膨化棉籽粕比起添加棉籽粕可显著降低生长猪血清中丙二醛(MDA)含量(P<0.05),显著提高生长猪的总抗氧化能力(T-AOC)、超氧化物歧化酶(SOD)活性和谷胱甘肽过氧化物酶(GSH-Px)活性(P<0.05);饲粮中添加膨化棉籽粕比起添加棉籽粕有提高生长猪血清中免疫球蛋白、三碘甲腺原氨酸和四碘甲腺原氨酸的趋势;随着膨化棉籽粕添加量的增加,生长猪的生长性能和营养物质表观消化率均呈现降低趋势,当添加量达15%时与普通棉籽粕组相比无显著差异(P>0.05)。3)育肥期,各膨化棉籽粕组末均重、平均日增重和平均日采食量与对照组和普通棉籽粕组相比差异不显著(P>0.05),但全期试验2组和试验3组料重比显著低于试验1组(P<0.05);饲粮中添加膨化棉籽粕比起添加棉籽粕还可以显著提高育肥猪的抗氧化能力和免疫能力(P<0.05),且随着膨化棉籽粕添加量的增加,育肥猪血清中MDA含量显著降低(P<0.05),T-AOC、SOD活性和GSH-Px活性显著升高(P<0.05)。试验组粗蛋白质表观消化率和干物质表观消化率均显著低于对照组(P<0.05),各膨化棉籽粕组粗蛋白质表观消化率与试验1组差异不显著(P>0.05),各膨化棉籽粕组干物质表观消化率均显著高于试验1组(P<0.05);试验3组和试验4组粗脂肪表观消化率显著高于对照组和试验1组(P<0.05),且随着膨化棉籽粕添加量的增加,粗脂肪表观消化率逐渐升高。饲粮中添加适量的膨化棉籽粕比起添加棉籽粕可显著提高氨基酸表观消化率(P<0.05)。由此可见,挤压膨化加工对棉籽粕营养物质含量影响较小,且能显著降低游离棉酚的含量,在生长育肥猪饲粮中添加膨化棉籽粕可以显著提高生长育肥猪的生长性能、抗氧化能力、免疫能力和营养物质表观消化率,生长猪饲粮中添加量可达15%,育肥猪饲粮中添加量可达20%。

The aim of the experiment was to investigate the effects of wet extrusion on the content of nutrients and free gossypol in cotton meal （CM） and explore the effects of extruded cotton meal （ECM） on growth performance, serum biochemical indices and nutrient apparent digestibility of growing-finishing pigs. Firstly, Muyang 56×2 expanding machine and the early optimized processing parameters were used to expand the CM, and the content changes of nutrients and free gossypol in CM and ECM were measured. Then, CM and ECM were used as the main experiment materials, and eighty pigs （Duroc×Landrace×Large White） with the body weight of （28.78±3.09） kg were randomly allocated to 5 groups with 4 replicates each and 4 pigs in each replicate （half male and half female）. Pigs in control group were fed an all corn-soybean meal basal diet, in experimental group 1 were fed the basal diet supplemented with 5% CM to growing pigs and 10% CM to finishing pigs, and in experimental groups 2, 3 and 4 were fed the basal diets supplemented with 5%, 10% and 15% ECM to growing pigs and 10%, 15% and 20% ECM to finishing pigs, respectively. The metabolic energy, crude protein content and other nutrition levels in all diets were balanced. The experiment lasted for 13 weeks with 6 weeks of growing period and 7 weeks of finishing period. The results showed as follows： 1） extrusion on CM had no obvious effects on nutrient content, and the contents of total amino acids and essential amino acids in ECM were increased slightly, while the free gossypol content in ECM was decreased by 87.85%. 2） In the growing stage, compared to 5% CM, dietary 5% ECM increased the average daily feed intake and average daily gain of pigs （ P 〉0.05）, significantly decreased the ratio of feed to gain （ P 〈0.05）, and significantly increased the apparent digestibility of crude protein, dry matter, ether extract and some amino acids （ P 〈 0.05 ）. Compared with CM, the serum malondialdehyde （MDA） content was significantly reduced, and the serum total antioxidant capacity （T-AOC）, superoxide dismutase （SOD） activity, glutathione peroxidase （GSH-Px） activity were significantly improved after the pigs were fed the diets supplemented with ECM （ P 〈0.05）. The serum contents of immunoglobulin, triiodothyronine and tetraiodothyronine tended to be enhanced of growing pigs by feeding the ECM compared with CM. With the addition of ECM increasing, the growth performance and nutrient apparent digestibility of the growing pigs showed a decreasing trend, and there was no significant difference between 15% ECM group and common CM group （ P 〉0.05）. 3） During the finishing stage, there were no significant differences in the final average body weight, average daily weight gain and average daily intake from the ECM groups to the control group and common CM group （ P 〉0.05）. However, the feed to gain ratio in experimental groups 1 and 3 was significantly lower than that in experimental group 1 during the whole stage （ P 〈0.05）. It can also significantly improve the antioxidant capacity and immunity of finishing pigs fed the ECM compared with the CM, and with the addition of ECM increasing, the serum MDA content of finishing pig was significantly decreased （ P 〈0.05）, and the serum T-AOC, activities of SOD and GSH-Px were increased gradually （ P 〈0.05）. Compare with the control group, the apparent digestibility of crude protein and dry matter was significantly lower than that in experimental groups （ P 〈0.05）. The crude protein apparent digestibility in ECM groups was not significant different compared with experimental group 1 （ P 〉0.05）. The dry matter apparent digestibility in ECM groups was significantly higher than that in experimental group 1 （ P 〈0.05）. The ether extract apparent digestibility in experimental groups 3 and 4 was significantly higher than that in the control group and experimental group 1 （ P 〈0.05）. With the addition of ECM increasing, the ether extract apparent digestibility was increased gradually. The addition of a moderate amount of ECM can significantly improve the apparent digestibility of amino acids compared with CM （ P 〈0.05）. Thus, the effects of extruded puffing on the nutrient contents of CM is not obvious, but can significantly increase the free gossypol content in CM. Dietary ECM can improve the growth performance, antioxidant capacity, immune capacity and nutrient apparent digestibility of growing-finishing pigs, and it is suggested that the amount of ECM for the growing pig is about 15%, and for finishing pig is about 20%.