| In this paper, three different acidifiers—Acid Lac, acidifier A1&A2,were conducted in diet for layers in summer to study their mechanism and effects, and sift suitable adding types and levels.A1 and A2 were all composed with phosphorus acid(40%50%), lactic Acid, citric acid, fumaric acid, cider acid, tartaric acid and excipient. 432 36-week-old Nick layers were randomly divided Eight treatments and three replicates, and each replicate had 18 hens. Basal diet of eight treatments was same. Group I (a negative control)was offered 0% acidifier, group II was added with 0.3% Lactic Acid, group ⅢⅤ and ⅥⅧ were respectively added A1 and A2 at the addiction level of 0.1%, 0.2% and 0.3%. The experiment were divided four parts: In Exp. 1, production performances of each treatment were measured; In Exp. 2, the whole-faece-collected method was used in metabolic trial to determine the effect of Acidifiers on apparent digestibility of dry matter (DM), general energy(GE) and crude protein(CP), the pH values and the acid binding capacity(ABC) of diet for each treatment were also measured. In Exp. 3, some blood serum bio-chemical indexes-ALP, LDH, TP, ALB, GLOB, A/Q, GLU, BUN, UA, pH, Ca and P were measured and counted. In Exp. 4,three randomly selected layers from every treatment were slaughtered to determine the pH value of digest tract; the digestive enzyme activity of duodenum; and the population of the E-coli, lactobacillus, bifidobacterium in the jejunum and cecum contents. The results were as follows: 1. Effect of acidifiers on layers in summerThree acidifiers were good to layers in summer, A2 was best and A1 was better. The optimum addition level of Al was 0.3%, A2 was 0.2% and 0.1%. The Lactic Acid was worse maybe because the addition dosage was too high.2 Effect of acidifiers on production performanceAcidifiers could increase the egg production rate, egg weight and feed intake of layers in summer, improve the quality of eggshell, reduce the rate of death, elimination and abnormal egg, but could not influence on feed efficiency. The group VI was better to egg production rate, and group V was superior to A2 and Lactic Acid group. As indicated, 0.1%0.3% of Al were 1.01%3.26% higher than the control group, while A2 were 1.85%2.87%. and Lactic Acid was 3.20%;abnormal egg rate reduced respectively 0.83%2.03%,2.86%3.24% and 0.2%; the rate of death and elimination decreased 1.8%3.7%.3 Effect of acidifiers on some bio-chemical indexesA1 and A2 were all superior to Lactic Acid group and the control group, and A2 was best. Acidifiers could increase the (?) and theconcentration of GLU, Ca (T2), P(T2); the activity of LDH and the concentration of BUN, UA, P(T1) and pH, but the concentration of Ca(Tl) and protein were no significant effect.4. Effect of acidifiers on inner enteron circumstancesAcidifiers could reduce the pH of digest tract contents; and increase the activity of trypsin and amylopsin, especially group VII was very significantly promoted (P<0.01), group V was significant (P<0.05). Acidifiers reduced the population of E. coli in jejunum and cecum, which were respectively 9.05%(P<0.05), 9.05%(P<0.05), 9.92%(P<0.05) and 4.0%, 6.78%, 9.69%(P<0.05) lower than the control group. But increased the population of lactobacillus, which were respectively 11.23%, 10.99%, 13.33%(P<0.05), and 4.02%, 9.99%(P<0.05), 12.06%(P<0.05) higher than the control group. The bifidobacterium were respectively 10.17%(P<0.05), 9.09%(P<0.05), 14.71%(P<0.01) and 2.48%,10.25%(P<0.05), 13.40%(P<0.05) higher than control group. In cecum, the population of lactobacillus and bifidobacterium of group VII were 7.73%(P<0.01) and 10.66% (PO.05) higher than group Lactic Acid.5. Effect of acidifiers on diet indexesLactic Acid, Al and A2 could respectively reduce the pH and ABC of diet from 5.45 to 5.14, 5.37 and 5.25; and from 21.71 to 17.67, 15.38, 8.63. Metabolic trial indicated: acidifiers could promote the feed intake, the content of GE,CP and the apparent digestibility of DM,GE and CP; and could decrease the defecation of faeces, DM and CP.6. Effect of acidifiers on heat stress of layers in summerThe results of all indexes in mis study indicated: Acidifiers could promote production performance, eggshell quality, decrease the death and elimination rate; improve acid-base-balance, and mitigate the heat stress of layers during the high temperature, so can be applied as an effective anti-stress additive.
|
PDF Full Text Request