Effects Of Dietary Chitosan Oligosaccharides-Clostridium Butyricum Synbiotics Supplementation On Growth Performance And Intestinal Health In Early Weaning Domestic Pigeon Squabs(Columba Livia)

After hatching,parental pigeons take care of the young squabs in turn,because squabs cannot take care of themselves until they are ready to leave nests,which severely limits the production of female pigeons and restricts the development of the pigeon industry.Hence,it is necessary for squabs to leave the nest to be fed by hand.It is obviously that synbiotics are beneficial for the growth performance and relieving earlyweaned stress on animals with its lower dosage and higher efficiency.The aim of this study was to explore the effects of early weaning on growth performance and intestinal health in 25-day-old squabs.Then,the effects of chitosan oligosaccharides-Clostridium butyricum synbiotics on growth performance and intestinal health in early-weaned domestic pigeon squabs(Columba livia)were researched in this experiment.1.Effects of early weaning on growth performance and intestinal health in domestic pigeon squabs(Columba livia)The aim of this study was to explore the effects of early weaning on growth performance,intestinal morphology,digestive enzyme activity,antioxidant status,and cytokine status in domestic pigeon squabs(Columba livia).A total of 160 White King Pigeon squabs(mixed sex,1 d of age)and 80 pairs of parental White King pigeons(80males and 80 females,1-year-old)were obtained from a commercial farm.Squabs in the same treatment were randomly pair-matched and allocated into nests of parental pigeons.The conclusion is based on body weight and average daily gain,length index and weight index of small intestine,small intestinal morphology,activity of digestive enzymes in duodenum content,the concentrations of jejunal antioxidant status and cytokines.A completely randomized design with the control group(CON)and early weaning(EW)group,was utilized.Eight squabs per treatment were sampled at the age of 25 d.The results showed that early weaning reduced body weight(P < 0.05),average daily gain(P < 0.05),ileac length index(P < 0.05),and weight index(P < 0.01).Compared with the CON group,small intestinal morphology was altered in the EW group.Ileac crypt depth increased significantly(P < 0.01).The villus area was decreased in the duodenum(P < 0.05),jejunum(P < 0.01),and ileum(P < 0.05).The ileac villus height to crypt depth ratio(VCR)in the EW group was lower than the ileac VCR in the CON group(P < 0.01).The activity of trypsin(P < 0.05),sucrase(P < 0.01)and aminopeptidase-N(P<0.01)in the duodenum content was reduced.Jejunal malondialdehyde(P < 0.01)was increased and total superoxide dismutase(P < 0.01)was reduced significantly.Early weaning decreased the concentrations of interferon-γ(P < 0.01),interleukin-4(P < 0.05)and interleukin-10(P < 0.01)but induced significant upregulation of interleukin-2(P < 0.05).2.Effects of chitosan oligosaccharides-Clostridium butyricum synbiotics on growth performance and intestinal health in early weaning domestic pigeon squabs(Columba livia)The aim of this study was to explore the effects of dietary chitosan oligosaccharides-Clostridium butyricum synbiotic on growth performance and intestinal health in early-weaned domestic pigeon squabs(Columba livia).A total of160 squabs at the age of seven days were randomly divided into 5 groups with 8replicates per group: the control group,fed with artificial crop milk;the chitosan oligosaccharides(COS)group,fed with artificial crop milk +150 mg/kg COS;and three synbiotic supplementation groups,fed with artificial crop milk +150 mg/kg COS +200,300 and 400 mg/kg Clostridium butyricum,respectively.The results showed that compared with the control group,dietary synbiotics supplementation had positive effects on growth performance(BW,ADG and survival rate)of squabs,and the differences were not significant(P > 0.05).The most significant increase in immune organ index was thymus index in CB2 group(P<0.05).The duodenal VH in CB2 group was significantly increased(P < 0.05)and duodenal crypt depth in CO group(P<0.05)and CB1 group(P < 0.01)was significantly decreased.Besides,duodenal villus surface area in CO group,CB2 group and CB3 group was increased significantly(P<0.05).The villus surface area of jejunum in CB2 group was significantly higher than that in control group and CO group(P<0.05).The villus height to crypt depth ratio(VCR)in duodenum in CB2 and CB3 groups was higher than that it in control group(P < 0.05).The digestive enzyme activity in duodenum contents of squabs were increased.The activity of lipase in CB2 group was significantly higher than it in CO group and CB1group(P < 0.05),and significantly higher than it in C group and CB3 group(P < 0.01).In addition,the concentrations of glutathione peroxidase and total antioxidant capacity were increased significantly in CB3 group,as compared with the control group(P <0.05).Besides,a significant decrease could be seen in CB2 group of the levels of interleukin-2(P < 0.01).The concentration of interleukin-4(P < 0.05)and interleukin-10(P < 0.01)in CB3 group was significantly increased in comparison with the control group.The total SCFAs(P < 0.05)and acetic acid(P < 0.01)in CB2 group were significantly increased,as compared with the control group.Moreover,compared with control group,the concentrations of butyric acid(P < 0.01)and valeric acid(P < 0.01)in CB2 group were significantly decreased.Our results showed that an increase of α-diversity in the gut microbiota by adding synbiotics into the diet.Chao1 index showed that the abundance index of the CB2 group was significantly higher than it in control group(P < 0.05).According to Shannon index,the α-diversity of microbial in CB3 group was significantly higher than it in control group and CB2 group(P < 0.01).Compared with control group,on the genus level,Proteobateria in CB2 group was significantly increased(P < 0.05).Compared with the control group,the relative abundance of Cyanobacteria and Actinobateteria in CB3 group were significantly increased(P < 0.01);on the phylum level,the relative abundance of Veillonella(P <0.05)and Saccharofermentans(P < 0.01)and Lachnospiraceae NK4A136 group(P <0.05)in CB2 group was significantly increased;the relative abundance of Bifidobacterium,Kocuria and Pseudarthrobacter in CB3 group was significantly increased(P < 0.05).Collectively,dietary chitosan oligosaccharides-Clostridium butyricum synbiotics supplementation could improve growth performance and intestinal health in early-weaned squabs.Under the condition of this experiment,considering the measured indexes,the appropriate level of chitosan oligosaccharides and C.butyricum supplementation may be 150 mg/kg chitosan oligosaccharides + 300～400 mg/kg Clostridium butyricum.