膨胀制粒对肉兔胃肠道发育和肠道生理机能的影响

Effects of Expansion Pelleting on Gastrointestinal Development and Intestinal Physiological Function of Rabbits

本试验旨在比较研究干压、蒸汽调质和膨胀制粒对肉兔胃肠道发育和肠道生理机能的影响。将72只平均体重为(918.85±5.71)g的伊高乐商品代肉兔按体重相近原则,随机分配到3组(每组6个重复,每个重复4只兔,公母各占1/2),分别饲喂同一饲粮配方下采用干压、蒸汽调质和膨胀制粒工艺生产的颗粒料。试验期35 d。饲养试验结束后,从每个重复选取1只兔屠宰取样,测定相关指标。结果表明:1)与干压和蒸汽调质制粒相比,膨胀制粒显著降低胃重和胃比重(P<0.05),显著提高小肠重和小肠比重(P<0.05),对盲肠重和盲肠比重无显著影响(P>0.05)。2)膨胀制粒比蒸汽调质制粒显著提高了十二指肠绒毛高度和肠绒隐比(P<0.05),显著降低了十二指肠隐窝深度(P<0.05);空肠和回肠绒毛高度、隐窝深度、绒隐比不同制粒工艺间无显著差异(P>0.05)。3)膨胀制粒比干压制粒显著提高了十二指肠脂肪酶和淀粉酶活性(P<0.05),比蒸汽调质制粒显著提高了淀粉酶活性(P<0.05),十二指肠胰蛋白酶活性不同制粒工艺间无显著差异(P>0.05)。膨胀制粒比干压制粒显著提高了盲肠半纤维素酶和果胶酶活性(P<0.05),显著降低了盲肠纤维素酶活性(P<0.05)。4)盲肠pH、总挥发性脂肪酸含量及各挥发性脂肪酸比例不同制粒工艺间无显著差异(P>0.05),但膨胀制粒比干压和蒸汽调质制粒显著降低了盲肠氨态氮含量(P<0.05),显著提高了盲肠双歧杆菌数量(P<0.05),同时比干压制粒显著提高了盲肠乳酸杆菌数量(P<0.05)。综上可知,在本试验条件下,膨胀制粒改善了肉兔十二指肠黏膜形态,促进了小肠发育,同时在不改变盲肠发酵模式下促进了盲肠有益菌繁殖,增强了肠道淀粉酶和可溶性纤维酶活性,有利于动物生长和健康。膨胀制粒比蒸汽调质和干压制粒更适合肉兔饲粮加工。

This study aimed to compare the effects of expansion pelleting,steam-conditioning pelleting and dry pelleting on gastrointestinal development and intestinal physiological function of rabbits.A total of 72 Hycole commercial rabbits at the age of 30 days and with an average body weight of(918.85±5.71)g were randomly divided into 3 groups with 6 replicates per group and four rabbits(2 male and 2 female)in each replicate.Rabbits in the 3 groups were fed the same formulated diet with 3 processing skills.The 3 processing skills were dry pelleting,steam-conditioning pelleting and expansion pelleting.The test lasted for 35 days.At the end of the feeding trial,one rabbit was selected from each replicate and slaughtered for sampling,and the relative indicators were determined.The results showed as follows:1)the weight and relative weight of stomach were significantly lower while those of small intestine were significantly higher in expansion pelleting group than those in dry pelleting and steam-conditioning pelleting groups(P<0.05).There were no significant differences in the weight and relative weight of cecum among the 3 groups(P>0.05).2)Expansion pelleting significantly increased the villus height and the ratio of villus height to crypt depth(P<0.05),while significantly decreased the crypt depth in duodenal compared with steam-conditioning pelleting(P<0.05).There were no significant differences in the villus height,the crypt depth and the ratio of villus height to crypt depth of jejunum and ileum among the 3 processing skills(P>0.05).3)Expansion pelleting significantly increased the activities of chylolipase and amylase in duodenum compared with dry pelleting(P<0.05),and significantly increased the activity of amylase in duodenum compared with steam-conditioning pelleting(P<0.05),and there was no significant difference in the activity of trypsin in duodenum among the three processing skills(P>0.05).Expansion pelleting significantly increased the activities of hemicellulase and pectinase in cecum(P<0.05),and significantly decreased the activity of cellulase in cecum compared with dry pelleting(P<0.05).4)There were no significant differences in pH,total volatile fatty acid content and each volatile fatty acid proportion among the 3 processing skills(P>0.05).However,expansion pelleting significantly decreased the content of ammonia nitrogen(P<0.05),and significantly increased the Bifidobacterium count in caecum compared with dry pelleting,steam-conditioning pelleting(P<0.05),and also significantly increased the Lactobacillus count in caecum compared with dry pelleting(P<0.05).In conclusion,under the conditions of this experiment,expansion pelleting improves the morphology of duodenal mucosa,the development of small intestine,the propagation of beneficial bacteria in cecum,and the activities of amylase and soluble cellulase in intestinal tract,which are beneficial to the growth and gastrointestinal health of rabbits.Compared with the steam-conditioning pelleting and dry pelleting,the expansion pelleting is more suitable for the diet processing of rabbits.