| The broiler industry is an important pillar of Guangdong's agricultural economy.For large-scale broilers,the impact of environmental factors has become more prominent.Temperature is an important environmental factor affecting broiler production.High temperature environment will damage the intestinal barrier function of broilers and reduce production performance.However,compared to fast-growing broilers,there are few studies on the effect of high temperature environment on local yellow feather broilers.Huaixiang chicken is a high-quality local yellow feather broiler breed in Guangdong,but the current research on its production performance and intestinal barrier function in high temperature environment is very lacking.Therefore,this experiment aims to study the influence of high temperature environment on the production performance,physiological and biochemical indicators and intestinal barrier function of Huaixiang chicken,and lay the foundation for the environmental control and the scientific prevention and control of adverse effects caused by high temperature environment.The experiment adopts a completely random grouping test design.Forty female nostalgic chickens with a age of 1 kg of about 56 days are selected as the test material.They are randomly divided into a normal temperature group and a high temperature group.Each group has 20 chickens.Each group is randomly divided into 5 repeats.4 cages as a repeat.Normal temperature group temperature control: 24 h 21 ± 1 ?,high temperature group temperature control: 9:00 am-17: 00 pm 32 ± 1 ?,the remaining temperature is maintained at 21 ± 1 ?,humidity is controlled at 50-70% between.The feeding cycle is 4 weeks.Give sufficient feed and drinking water during the test.Serum was collected one day before slaughter to determine the lipid content in the serum;the abdominal muscles,pectoral muscles,leg muscles,heart,liver,liver,spleen,kidney,pancreas,muscular stomach and glandular stomach of Huaixiang chicken were weighed,and the chest and leg muscles were measured.Muscle quality;take the duodenum,jejunum and ileum tissue-like and intestinal contents.RNA was extracted from intestinal tissues,and the relative expression of genes related to intestinal barrier function was detected by q PCR;the metabolic group of cecal contents was analyzed by LC-MS;and the composition of cecal microbial flora was determined by 16 S high-throughput sequencing technology.The production performance results show that:(1)the weight gain of the high temperature group is significantly lower than that of the normal temperature group(P <0.05);the difference in feed intake and feed-weight ratio is not significant(P> 0.05);(2)the percentage of abdominal fat in the high temperature group The average value is significantly higher than the normal temperature group(P <0.01),the average value of the leg muscle rate in the high temperature group is significantly lower than the normal temperature group(P <0.01),and the difference in the chest muscle rate is not significant(P> 0.05);There was no significant difference in the weight of organs in the township chickens(P> 0.05);there was no significant difference in the cooking loss of the pectoral muscles between the high temperature group and the normal temperature group(P> 0.05).The drip loss in the high temperature group was significantly higher than the normal temperature group in the three-day test period(P <0.01);the pectoral muscle p H of the high temperature group was significantly lower than that of the normal temperature group at 45 minutes after slaughter(P <0.05),but the p H measured after 24 hours after slaughter was not significantly different between the two groups(P> 0.05);The cooking loss of leg muscles in the group and the normal temperature group and the drip loss of the leg muscles in the high temperature group were not significantly different in the three-day experiment after slaughter(P> 0.05),and the p H of the leg muscles in the high temperature group was significantly lower than normal temperature after 45 minutes of slaughter.Group(P <0.05),and the difference in p H at 24 h after slaughter(P> 0.05);(3)the content of catalase(CAT,Catalase)in the breast muscle of Huaixiang chicken in high temperature group was significantly lower than that in normal temperature group(P <0.05).0.05),the content of malondialdehyde(MDA,Malondialdehyde)was significantly higher than that of the normal temperature group(P <0.05);the total antioxidant capacity(T-AOC,Total antioxidant capacity)and total There was no significant difference between oxide dismutase(T-SOD,Total superoxide dismutase)and glutathione peroxidase(GSH-PX,Glutathione peroxidase)(P> 0.05).The content of GSH-PX in the high temperature group of leg muscles was significantly lower than that in the normal temperature group(P <0.05),while the changes of T-AOC,T-SOD,CAT and MDA in the high temperature group and normal temperature group were not significant(P> 0.05).The effect of high temperature on the physiological and biochemical indicators of Huaixiang chickens showed that:(1)The rectal and fin temperature of Huaixiang chickens in the 1-4 week high temperature group were significantly higher than that in the normal temperature group,and the fourth week eyelid temperature and left calf skin in the high temperature group The temperature was significantly higher than the normal temperature group(P <0.05);(2)the serum and excretion cortisol content of the Huaixiang chicken in the high temperature group were significantly higher than that in the normal temperature group(P <0.05);(3)the Huaixiang chicken in the high temperature group The serum T-AOC was significantly lower than that in the normal temperature group(P <0.05),and there was no significant difference in the contents of T-SOD,GSH-PX,CAT,and MDA;(4)The serum triglyceride and cholesterol levels in the high temperature group Huaixiang chicken serum The content was significantly higher than the normal temperature group(P <0.05),and the content of high-density lipoprotein and low-density lipoprotein had no significant difference between the two groups(P> 0.05).The test results of the intestinal barrier function of Huaixiang chicken showed:(1)Observing the small intestine tissue sections stained with HE,the villi height of the duodenum and ileum of Huaixiang chicken in the high temperature group was significantly lower than that in the normal temperature group(P <0.05),There was no significant difference in small intestinal villi width,crypt depth,and intestinal villi surface area between two groups of Huaixiang chickens(P> 0.05),but the ratio of ileum intestinal villi height and crypt depth in high temperature group was significantly lower than that in normal temperature group(P <0.05),but there was no significant change in duodenum and jejunum(P> 0.05);(2)CAT and MDA in duodenum,jejunum,and ileum of Huaixiang chicken in high temperature group were significantly lower In the normal temperature group,the T-AOC of the two groups of nostalgic chickens had no significant difference in the duodenum(P> 0.05),but the high temperature group in the jejunum and ileum was significantly lower than the normal temperature group(P <0.05).The GSH-PX of duodenum and jejunum in Huaixiang chicken in group was significantly lower than that in normal temperature group(P <0.05),but there was no significant change in ileum,and the T-SOD in duodenum and ileum in Huaixiang chicken in two groups was not significant Sex difference(P> 0.05),but the T-SOD content in the jejunum of Huaixiang chicken in the high temperature group was significantly reduced(P <0.05);(3)the relative expression of occludin and zo-1 genes in the duodenum of the normal temperature group The amount was significantly higher than that in the high temperature group(P <0.05),and the relative expression of occludin,claudin-1,claudin-4,zo-1,mucin-2 genes in the jejunum of the normal temperature group was significantly higher than that in the high temperature group(P <0.05),while the normal temperature Only the expression of claudin-4 in the jejunum of the group was significantly higher than that of the normal temperature group(P <0.05);(4)A total of 18 differential metabolites were screened by cecum potential biological metabolites screening,of which 12 were down-regulated metabolites and 6 were Up-regulation of metabolites,and further analysis of the KEGG metabolic pathways showed that these differential metabolites were mainly enriched in the tricarboxylic acid cycle and other pathways;(5)There was no significant difference in the Alpha index of the cecal flora of Huaixiang chicken in the high temperature group and the normal temperature group(P> 0.05),and there was no significant difference between the two groups of Huaixiang chicken cecum flora at all levels(P> 0.05).The above test results show that a high temperature environment around 32 ° C will significantly reduce the growth performance,muscle quality and antioxidant performance of 56-day-old female nostalgic chickens,and damage the morphological structure of the small intestine,reduce the antioxidant performance of the small intestine and affect the intestinal barrier Function-related gene expression changes the cecum metabolic group,but has no significant effect on the composition of the cecum flora. |
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