表观可消化苏氨酸对脂多糖应激条件下肉兔营养物质表观消化率、肠道形态和抗氧化能力的影响

Effects of Apparent Digestible Threonine on Apparent Digestibility of Nutrients,Intestinal Morphology and Antioxidant Capacity of Meat Rabbits Challenged by Lipopolysaccharide

本试验旨在研究饲粮添加不同水平表观可消化苏氨酸(AFDT)对脂多糖(LPS)诱导的肠道损伤肉兔营养物质表观消化率、肠道形态和抗氧化能力的影响。采用2×3双因子试验设计,应激处理分别为腹腔注射100μg/kg BW LPS或等量的生理盐水,饲粮AFDT水平分别为0.43%、0.54%和0.64%。选取初始体重[(808.11±12.17)g]相近、健康的35日龄断奶新西兰白兔180只,随机分为6组,每组30个重复,每个重复1只兔。试验周期35 d,分别于试验第17天和第20天早晨进行注射,试验第22天进行称重、屠宰,并采集肠道组织和黏膜样。试验结束后的第4天至第7天进行粪便样品采集(第3天和第6天进行腹腔注射100μg/kg BW LPS或等量无菌生理盐水)。结果表明:1)饲粮添加AFDT显著提高了肉兔的苏氨酸表观消化率(P<0.05),显著降低了干物质(DM)、无氮浸出物(NFE)和丙氨酸(Ala)表观消化率(P<0.05),显著降低了十二指肠总抗氧化能力(T-AOC)(P<0.05)。2)LPS应激显著降低了肉兔DM、有机物(OM)、总能(GE)、NFE、酸性洗涤纤维(ADF)和半胱氨酸(Cys)的表观消化率(P<0.05),显著降低了空肠的绒毛高度(VH)以及十二指肠的丙二醛(MDA)含量(P<0.05),显著增加了空肠MDA含量和T-AOC(P<0.05)。3)饲粮AFDT水平与LPS应激互作对肉兔十二指肠VH、回肠T-AOC、MDA含量以及黄嘌呤氧化酶(XOD)和谷胱甘肽过氧化物酶(GSH-Px)活性有显著影响(P<0.05)。LPS应激条件下,添加AFDT显著增加了十二指肠VH和回肠GSH-Px活性以及降低了回肠XOD活性(P<0.05),有降低回肠MDA含量的趋势(P=0.07)。综上所述,饲粮添加AFDT可缓解LPS应激造成的肉兔肠道形态受损和氧化应激,从而减轻LPS应激对肉兔肠道造成的损伤。

This study was conducted to investigate the effects of apparent digestible threonine(AFDT)on apparent digestibility of nutrients,intestinal morphology and antioxidant capacity of meat rabbits with intestinal injury induced by lipopolysaccharide(LPS). A 2×3 two factors design was used in this experiment. Two kinds of challenge treatments were intraperitoneal injection of 100μg/kg BW LPS or equivalent physiological saline;AFDT levels were 0.43%,0.54% and 0.64%,respectively. A total of 180 healthy 35-day-old weaned New Zealand white rabbits with similar initial weight[(808.11±12.17)g]were selected and randomly divided into6 groups,with 30 replicates in each group and 1 rabbit in each replicate. The experiment lasted for 35 days,and was injected on the morning of days 17 and 20. On day 22 of experiment,weighed,slaughtered and collected intestinal tissue and mucosa samples. Fecal samples were collected from days 4 to 7 after the experiment(intraperitoneal injection of 100μg/kg BW LPS and the same amount of sterile normal saline were given on days 3 and 6). The results showed as follows:1)dietary AFDT significantly increased the apparent digestibility of threonine(P<0.05),significantly decreased the apparent digestibility of dry matter(DM),nitrogen-free extract(NFE)and alanine(Ala)(P<0.05),and significantly decreased the total antioxidant capacity(TAOC)of duodenum(P<0.05). 2)LPS challenge significantly decreased the apparent digestibility of DM,organic matter(OM),gross energy(GE),NFE,acid detergent fiber(ADF)and cysteine(Cys)of meat rabbits(P<0.05),significantly reduced the villus height(VH)of jejunum and the malondialdehyde(MDA)content in duodenum(P<0.05),and significantly increased the MDA content and T-AOC of jejunum(P<0.05). 3)There was significant interaction between dietary AFDT level and LPS challenge on VH in duodenum,and T-AOC,MDA content,xanthine oxidase from buttermilk(XOD)and glutathione peroxidase(GSH-Px)activities in ileum in meat rabbits(P<0.05). It was showed that under the conditions of LPS challenge,AFDT significantly increased VH in duodenum and GSH-Px activity in ileum(P<0.05),and decreased XOD activity in ileum(P<0.05),which had a tendency to decrease MDA content in ileum(P = 0.07). In conclusion,the supplementation of dietary AFDT alleviates intestinal morphology damage and oxidative stress which induced by LPS challenge to a certain extent,and alleviates negative impact of meat rabbits challenged by LPS.[Chinese Journal of Animal Nutrition,2023,35(1):579-592]