Effects Of Release Rate Of Sodium Butyric On Growth Performance And Gastrointestinal Development Of Pre-Weaning Calves

The purpose of the current study was to study the growth performance,gastrointestinal mucosal morphology,and digestive enzyme activities of gastrointestinal of lactating Holstein bull calf with three different release rates of sodium butyrate in starter.The detail with four parts is given as following.Experiment 1:Determination of release rate of sodium butyrate in vitro with different envelopeTwo different release rates of sodium butyrate were used to simulate the release rate of gastrointestinal environment in vitro.The results showed that most of the coated sodium butyrate was released in the intestinal tract.The loss rate of coated sodium butyrate in simulated gastric juice was 14.5%for 1h and 24.9%for 2h,respectively.The loss rate of coated sodium butyrate in simulated gastric juice was 9.9%for 1h and 13.1%for 2h.The loss rates of coated sodium butyrate were 39.8%,59.5%and 79.1%in intestinal fluid for 2 h,4h and 8h,respectively.The loss rate of coated sodium butyrate was 24.7%,39.3%and 59.9%in intestinal fluid for 2h,4h and 8h,respectively.The following two release rates of coated sodium butyrate are called coated sodium butyrate(fast)and coated sodium butyrate(slow).Experiment 2:The effects of different release rates of sodium butyrate on growth performance and senim indexes of calvesIn the present experiment,the effects of sodium butyrate on growth performance and serum indexes of calves were studied by adding sodium butyrate at different release rates in starter.Forty healthy calves within 5 d after birth were divided into four groups based on the principle of birth weight and average distribution of day age.In the control group,0.3%sodium butyrate(no coating),coated sodium butyrate(fast)and coated sodium butyrate(slow)were added to trial group 1,2,and 3,respectively.All the four groups with starters and whole milk offered ad libitum and other conditions were the same.The experiment period were 60 d,the daily feed intake and diarrhea of calves were recorded.The birth weight of calves was weighed and recorded once every 20 d.During the experiment,venous blood samples were taken from the calves at the mean age of 34 d and 58 d for the determination of serum indexes.The results showed that:(1)there was no significant difference in the feed intake and daily gain(P>0.05).(2)comparing with the control,the diarrhea rate in the sodium butyrate supplemented groups was significantly lower(P<0.01).sodium butyrate and coated sodium butyrate(fast)was significantly lower than that of coated sodium butyrate(slow)group.(3)the addition of sodium butyrate in starters decreased the GLU,TG,UN,and CHO in blood of calves with different release rates of sodium butyrate at different days of age significantly(P<0.01),and increased the concentration of TP,Ca,P,EGF,and IGF-1 in the blood of calves(P<0.01).The effects were significantly different with row of group 3,group 2 and group 1(P<0.01).Therefore,the daily gain of calves fed with sodium butyrate had no significant difference,but it could decrease the diarrhea rate and improve the biochemical and growth factor indexes of calf serum.Experiment 3:The effects of different release rate of sodium butyrate on gastrointestinal development of calfAccording to the development indexes of gastrointestinal,pancreatic tissues,and organs of calves,the differences of these parts of calves were compared in this experiment with different release rates of sodium butyrate in starter.According to the principle of similar body weight of calves,four calves in each group were slaughtered on the day of weaning.The relative weight of stomach in the release rate slow coated sodium butyrate group was significantly lower than that in the other three groups(P<0.05).The papilla length and thickness of the base layer were increased in the sodium butyrate group(P<0.05),and the thickness of the abomasum mucosa was increased with sodium butyrate addition(P<0.05).The height of villi,the depth of recess and the thickness of the mucosa in jejunum were increased by sodium butyrate at sodium butyrate.Experiment 4:The effects of different release rate of sodium butyrate on digestive enzyme activity of calves.The experimental design and feeding scheme are the same as the second experiment,and the slaughtering scheme is the same as the third experiment.The results showed that the activities of trypsin,chymotrypsin,and lipase in duodenum of sodium butyrate group were significantly lower than those of coated sodium butyrate group,and the chymotrypsin activity of sodium butyrate group was significantly lower than that of the control(P<0.05).Release rate of sodium butyrate at increased trypsin activities in ileum(P<0.01).In summary,supplement with sodium butyrate can reduce diarrhea rate and improve blood index.The effects of uncoated sodium butyrate acted on mainly in the rumen and the proximal small intestine,and the coated sodium butyrate acted on mainly in the distal small intestine and the large intestine.