Effects Of Threekinds Of Feed Additives On Growth And Development Of Chick And Small Intestine

In recent years,feed additives,such as probiotics,acidifiers,enzymes are often added to the diet in laying hen farms,which can not only change the nutritional metabolism,but also improve the production,feed conversion efficiency and the healthy state of digestive tract of laying hens.In order to provide reference for the application of different additivesin laying hens production,two experiments were conducted to investigate theeffects of diets supplemented with three kinds of feed additives on growth and small intestine of chick.In first experiment,a total of 384 1-d-old male Hyline brown chicks were randomly allocated to four groups,each with six replicate sets of 16 birds.In second experiment,a total of 288 6-wk-old male Hylinebrown chicks were randomly divided into four groups,each with six replicate sets of 12 birds.In both experiments,the control group(Group A)was fed with basic diet,whereas three experimental groups(Group B,C,and D)were fed basic diet supplentmented with sodium butyrate(0.5%),mannan oligosaccharide(0.5%),and the complexes of probiotic bacteria(1 ×107CFU/g),sodium butyrate(0.5%)and mannan oligosaccharide(0.5%),respectively.The growth performance,serum biochemical index,organ index and small intestine morphology were observed in both experiments.The results showed that:1.At the age of 3 to 6 week,the body weight of group D was significantly higher than that of group A(P<0.01).At the age of 6 week,the body weight of experimental groups were 9.6%,10.5%,7.3%and 7.3%higher than that of group A,respectively.Compared with group A,the average daily intake and average daily gain of group D were increased by 2.6%and 7.8%respectively,and the feed-to-weight ratio decreased by 4.8%(P<0.01).Compared with group A,the feed-to-weight ratio for 7 to 8 week period in group D was reduced by 16.3%(P<0.05)2.At the age of 6 week,theserum immunoglobulin G concentrations in group B and group C were higher than those in group A(P<0.05),and increased by 82.0%and 113.4%respectively.At the age of 8 week,there were no differences in blood biochemical and immune indices between the treatment groups(P>0.05).3.At the age of 6 and 8 week,there were no differences in visceral organ index between the four groups(P>0.05).4.Compared with group A,the villus height of ileum in group D increased by 31.2%at the age of 6 week(P<0.05).At the age of 8 week,the villus height of duodenum in group B and group Dincreased by 1.8%and 2%,respectively(P<0.05).The crypt depth of jejunum in group D was lower than that in group C(P<0.05).Compared with group A,the crypt depth of jejunum in group D was reduced by 3.5%(P<0.05).At the same time,compared with group A,the villus height/crypt depth of jejunum in group B and group D increased by 7.1%and 8.7%respectively(P<0.01),and the villus height of ileum in group D increased by 6.4%(P<0.05).In summary,the addition of sodium butyrate,mannooligosaccharide,and the complexes of probiotics,sodium butyrate and mannooligosaccharide improved the growth performance and had a positive effect on small intestinal morphology in the early stageof layer chickens.Moreover,the complexes of three kinds of feed additives have a better effect.