| Postpartum estrus of ewe and stress factors during feeding management can significantly affect the production of Small-tail Han(STH)sheep.Recognizing and utilizing postpartum estrus,reducing stress factors and enhancing the adaptive ability of stress have positive significance to improve feeding management of STH sheep and to improve the benefit of animal husbandry,and also have great reference value to scientific breeding of other economic animals.To study the behavior,endocrine and ovarian gene expression of STH ewes with different intervals between lambing and estrus,and determine the key factors which affected postpartum estrus of female STH sheep and reveal its regulatory mechanism,we selected 10 healthy and adult ewes which would be lambing,and studied the daily behavior and hormone changes during the interval between lambing and estrus by scanning sampling and fecal hormone assay,then slaughtered these ewes and removed the ovaries for analyzing the difference of mRN A expression by RNA-seq technology at the time of estrus;To reveal the synergistic mechanism between behavior and physiology,explore the regulation and adaptation mechanism of animals under stress.We studied the behavior and physiological changes under thermal environment,shearing,transportation and isolation.Sum up,the results of this study are useful and can provide reference basis for improving postpartum estrus and stress adaptation of STH sheep.The main results were as follows:1.The behavior,endocrine and ovarian gene expression of STH ewes with different intervals between lambing and estrus(1)All tested ewes were divided into 2 groups according to the interval between lambing and estrus:the ewes in Group I were with the interval of 47±7 days between lambing and estrus and the ewes in Group II were with the interval of 65±7 days between lambing and estrus.There were some differences in behavior and reproductive hormone of STH ewes with different postpartum estrus interval.Behaviorally,there are more standing and exploring in group ? than that in group?,and fewer ruminating in group I than that in group II.The looking decline first and then increase in group ? while increase first and then decline in group II during the interval between lambing and estrus.In terms of hormone,there are more fecal hormone of FSH,LH,E2 and P in group ? than that in group ?,while less fecal hormone of MLT in group I than that in group ?.(2)RNA-seq technology was employed to analyze the deferentially expressed genes(DEGs)in the ovary of STH ewes with different intervals between postpartum and estrus at the time of estrus.There were 390 DEGs which were identified,including 230 up-regulated genes and 160 down-regulated genes.Go functional enrichment analysis showed that the DEGs were significantly enriched in behavior,growth,development,metabolism biological process and transcriptional regulation,molecular conduction,transport,catalysis and other molecular functions.So,it is speculated that these DEGs played an important regulatory role in estrus enablement after lambing of STH ewes.2.The behavioral and physiological changes under stress conditons of thermal environment,shearing,transport and isolation(1)16 healthy and adult STH sheep(8 rams and 8 ewes)with similar body conditions were selected to study the effect of heat on the behavior and physiology,the result showed that high temperature obviously changed the behavior,physiology and blood endocrine of the STH sheep.There were some significant differences of behavior(standing,P=0.001;walking,P=0.049;ruminating,P=0.010),physiology(Respiratory Rate,P=0.0001;Heart Rate,P=0.002;Rectal Temperature,P=0.03),blood minerals and metabolites(sodium,P=0.047;phosphorus,P=0.002;T4,P=0.041;cortisol,P=0.0047;triglyceride,P=0.009)between rams and ewes and that heat stress also significantly affected(P<0.05)standing,lying,foraging and drinking behavior,all of the physiological parameters and some of the blood chemistry parameters(chlorides,sodium,phosphorus,total protein,tetraiodothyronine,cholesterol,triglyceride,creatinine,cortisol,and glucose).These results indicate that ewes had better high-temperature tolerance than rams.(2)9 rams and 13 ewes which were healthy and adult and with similar body conditions were selected to study the effects of shearing on their behavior and physiology,the results showed that shearing produced acute intensive stress to STH sheep,and increased the behavior of blinking,tail wagging,head rising in ewes and rams,the blood ACTH and GH of ewes first increased and then declined with the process of shearing and showed significant changes(P<0.05).There were some differences in these parameters between male and female sheep:There were more blinking and bleating in ewes than that in rams during shearing(P=0.006,0.022).There were some significant differences in ACTH,CA,T4 between rams and ewes at the ending of shearing(P=0.050,0.004,0.029),and plasma ACTH and T3 in rams were higher than that in ewes 10 minutes after the ending of shearing(P=0.037,0.031).In comparison,the stress tolerance of rams was stronger than that of ewes.The foraging,drinking,ruminating and walking increased and the standing,rectal temperature and respiratory frequency declined after shearing.(3)8 rams which were healthy and adult and with similar body conditions were selected to study the effects of transport on their behavior and physiology,the results showed that transport could affect the behavior and physiology,and change daily behavioral rhythm of STH sheep.Behaviorally,ruminating and grooming decreased;standing,walking,foraging,exploring and looking increased first and then decreased;while lying decreased first and then increased.Transport also significantly affected the physiological parameters of Small-tail Han sheep:Compared to before transport,the blood GH of STH Sheep during 1 day after transport significantly increased(P<0.05),while the blood GLU significantly decreased during the whole transport(P<0.05),and no significant changes were observed in other blood metabolites.(4)11 rams which were healthy and adult and with similar body conditions were selected to study the effects of isolation on their behavior and physiology,the results showed that isolation could obviously affects the behavior and physiology of STH sheep.Behaviorally,moving,observing increased and standing,relaxing decreased after isolation,but only for 1 isolated group there were obvious changes(P<0.05).For daily behavior rhythm,these behavior all changed obviously after isolation,but these changes became less pronounced with the process of isolation.In terms of physiology,the blood Leptin declined significantly after 1 isolation,while the blood T4 increased significantly after 2 and 3 isolation. |
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