| Although dairy buffaloes have heat resistance,the lactation and reproductive performance would decrease under high temperature and high humidity in summer,and adversely affects the growth of calves.With the improvement of lactation performance of dairy buffaloes,the negative effects are more serious in summer.Although spraying,fan and rolling could effectively reduce rectal temperature,respiratory rates and improve production performance of buffaloes,wasting many resources in physical cooling and there is a certain pollution to the environment.Thus,the nutritional strategy,for example the feed additives,to improve production performance have their unique advantages.The purpose of this research was to investigate the effects of Capsicum oleoresin（CAP）addition on lactation performance and follicular dynamics of dairy buffaloes in summer,and to research its mechanism by analyzing rumen fermentation indicators,intestinal microbial composition,physiological and blood indicators.1.The prolactation effect of CAP on dairy buffaloes and its mechanismIn order to investigate the prolactation effect of CAP and its mechanism,and determine the optimal dosage,in vitro rumen fermentation and feeding tests were conducted.In the experiment in vitro,2×5 factorial design was carried out according to two temperatures（normal temperature:39℃;hyperthermal temperature:42℃）and five CAP concentrations（0 mg/L;2 mg/L;20 mg/L;200 mg/L;2000mg/L）.In the experiment in vivo,four midlactating Mediterranean buffaloes were randomly allocated to four treatments according to 4×4 Latin square design for CAP supplementation in four dosages（0 mg,10 mg,20 mg,or 40 mg CAP per kg dry matter）.The experiment’s results in vitro showed that hyperthermal temperature affected all fermentation characteristics in this research.CAP decreased the p H,volatile fatty acids（VFA）concentration,and percentages of propionate,butyrate,isobutyrate,valerate,and caproate,while increasing the percentage of acetate and the ratio of acetate to propionate at normal temperature（P<0.05）.Under high heat conditions,CAP decreased the concentration of ammonium,percentages of acetate,isobutyrate and valerate,and the ratio of epropionate,while increasing the percentage of propionate,butyrate and caproate.In the experiment in vivo,CAP decreased the percentage of propionate（P≤0.05）.CAP decreased rectal temperature and respiratory rates（P<0.05）and tended to increase dry matter intake quadratically（P<0.10）.For lactation performance,CAP increased milk yield and milk lactose yield（P<0.05）,and tended to increase milk protein yield（P<0.10）.In conclusion,CAP modified rumen fermentation characteristics in vivo and in vitro and had beneficial effects on lactation performance in buffaloes during summer.2.Effects of CAP on follicular development and reproductive hormone secretion in buffaloesTo explore the effect and mechanism of CAP on follicular development and reproductive hormone secretion of dairy buffaloes.Fourteen buffaloes were divided into2 groups:（0 mg or 20 mg CAP per kg of dry matter）and process for 30 d pre-feeding period.All buffaloes were subjected to GPG simultaneous estrus on 31 d:intramcular injection of gonadotropin-releasing hormone（Gn RH）on 31 d,chlorprostaglandin（PGF2α）on 38 d,and Gn RH again on 40d.Follicle dynamics were measured twice a day from 37d to 41 d,and corpus luteum diameter was measured at 51 d.Serum samples were collected at 31 d and 41 d,respectively,and detected reproductive hormones.The results showed that CAP had no effect on ovulatory follicle diameter（P>0.05）,while increased follicle development speed（P≤0.05）.In terms of reproductive hormones,CAP had no effect on blood estrogen concentration（P>0.05）,while tended to increase progesterone concentration（P<0.10）.In conclusion,CAP supplementation could accelerate follicular development,increase progesterone secretion from luteum,and may improve reproductive performance of buffaloes when low serum progesterone concentration in summer.3.Effect and mechanism supplement of CAP on colostrum quality and buffalo calves’growth performanceThis research aims to evaluate the effects of prepartum maternal supplementation of CAP on colostrum quality and growth performance in newborn buffalo calves.Twelve multiparous buffaloes were randomly assigned to two groups starting from 4 weeks prepartum:0 mg（CON）or 20 mg CAP/kg dry matter supplemented in the diet（CAP）.After birth,all calves were weighed and received colostrum from their respective dam directly within 2 h.After that,calves received pasteurized milk and starter feed till 56 d of age.The results showed that CAP increased lactose（P<0.05）in colostrum,and tended to increase monounsaturated fatty acids（P<0.10）;however,decreased colostrum urea nitrogen（P<0.05）.CAP did not affect colostrum yield and immunoglobulin G and M concentrations.The weekly starter intake was not affected by maternal CAP supplementation during the first 6 weeks of life;however,there was an increasing tendency in weekly starter intake in weeks 7 and 8（P<0.10）in CAP compared with CON.At 7 d of age,calves in CAP had higher immunoglobulin G（P<0.05）and a decreased tendency in calves’serum glucose compared with CON.Additionally,maternal CAP supplementation increased calves’serumβ-hydroxybutyric acid（P<0.05）and tended to increase total protein（P<0.10）,while decreased non-esterified fatty acids（P<0.05）at 56 d of age.Calves in CAP had higher final withers height,final heart girth,average withers height,and average heart girth than the CON（P<0.05）.Therefore,CAP supplementation can improve primary milk quality,change calves’blood indexes,and promote calves’growth.4.Effects of CAP on rumen and faeces microflora of dairy buffaloes in summerTo investigate the effects of CAP on intestinal microflora of milk buffalo,10midlactation buffaloes were randomly divided into 2 groups:0 mg（CON）or 20 mg CAP/kg dry matter supplemented in the diet（CAP）according to a 5 repeat 2×2alternating design.Rumen fluid and feces samples were collected after the pre-feeding period.After that,CON and CAP group were transferred for treatment,and samples were collected after the pre-feeding period.The V3+V4 hypervariable regions were sequenced using Illumina Mi Seq platform to analyze the microorganisms of all samples.The results showed that CAP had no effect on the Alpha diversity of rumen and fecal microorganisms（P>0.05）.In rumen microorganisms,CAP increased the abundance of uncultured＿bacterium＿f＿Planococcaceae compared with CON group（P<0.05）,and tended to increase the abundance of Spirochaetes and Treponema＿2（P<10）.Meanwhile,CAP tended to decrease the abundance of Ruminococcaceae＿UCG＿009 and Prevotella＿9（P<0.10）.In faecal microorganisms,CAP tended to increase the abundance of Cyanobacteria,Bacteroidales＿bacterium＿Bact＿22,and Comamonas compared with the CON group（P<0.10）.Additionlly,CAP tended to reduce the Rikenellaceae＿RC9＿gut＿group,unclassified＿Ruminococcaceae,uncultured＿rumen＿bacterium,unclassified＿RF39,Prevotellaceae＿UCG＿004,and U29＿B03 abundance compared with the CON group（P<0.10）.In conclusion,rumen microorganisms were different from fecal microbes,and their responses to CAP were inconsistent.CAP had no effect on rumen and fecal microbial Alpha diversity,but it could change the relative abundance in part of rumen and fecal microorganisms.Thus,CAP could promote nutrient degradation and absorption in intestinal tract and improve nutrient intake of buffaloes under high temperature conditions.In conclusion,the addition of CAP to dairy buffaloes in summer changes rumen fermentation,reduces rectal temperature and respiratory rates to improve dry matter intake and lactation performance.Meanwhile,CAP increased follicular development rate and serum progesterone concentration,which could improve reproductive performance of seasonal milk buffalo.Prenatally added CAP could improve colostrum performance and increase starter intake and growth performance of calves.In terms of microbial composition,CAP did not change rumen and faecal microbial in Alpha diversity,but could change the relative abundance of some microorganisms. |
PDF Full Text Request