The Effects Of Early Feeding On The Development Of Digestive System, Immune System And Production Performance Of Broilers

The present study was consisted of two parts. The influence of early feeding on the development of digestive system and immune organ of newly hatching broilers were investigated in the first part. After that we investigated the effect of early feeding on growing performance, nitrogen sediment,brisket yield and immune function in a feeding experiment.Experiment 1: 160 newly hatched broilers were randomly assigned to the eight groups. Each four groups receive the same treatment. Broilers receiving early feeding treatment were fed the routine foodstuff immediately after hatching. The early fasting broilers were fed the same foodstuff after 48h hatching. On day the hatching and 1,2,3,5, 7,10, 14 days after hatching. 2 chicks from each group were weighed and killed. Liver, pancrease, small intestine, gizzared, proventriculus, spleen, bursa, residual yolk were weighed; the activities of amylase,lipase and trpsin and the antibody level of yolk liquid were measured. The result indicated that: 1. The average live weight of broilers receiving early feeding was higher than that of the early fasting (p<0.05) .2. The index of proventriculus and jejunum of early feeding were higher than that of early fasting (p<0.05) .The average weights of other digestive organs have no significant difference between two groups (p> 0.05) . 2. The activity of amylase, lipase and trpsine of pancrease and amylase in jejunum of early feeding broilers were higher than that of early fasting broilers (p<0.05) .The activity of amylase and protease of the early feeding were not measured at the first 2 days. 3. Compared with early fastingbroilersi early feeding broilers have higher absolute and relative weight of immune organs (p<0.05) . 4. The weight of yolk sac of early feeding broilers was not significant difference to that of early fasting broilers (p > 0.05) . Yolk sacof the two groups disappeared at 5 day.200 newly chickens were randomly divided into 8 groups. Each four groups received the treatment. One was early feeding treatment, the other was early fasting treatment. The early feeding broilers were fed at about 3h after hatching. The early fasting broilers were fed at about 48h after hatching. Form the third after hatching, using routine diet to replace 25%^ 50% and 75% of the ultra-early diet of the early feeding broilers. At 21d, 42d and 49d of age, the body weight were determined after fasted for 10 hours, averages of daily gain, feed intake, feed efficiency and mortality rate were calculated. The blood sample was obtained form the wing vein,serum urine nitrogen and antibody level were analyzed.At 21d and 42d of age, 2 chicks of each groups were chosen to do nitrogen metabolism test. The experiment was divided into the probationary period and the formal period. Sludge and foodstuff were obtained to measure content of nitrogen. When the test was over, 2 chickens form each groups were slaughted, brisket ,spleen, bursa and thymus were weighed. The result indicated that: l.The average daily gain of early feeding was higher than that of early fasting broilers (p<0.05) .During the period 0-21 day, the feed conversation rate, nitrogen deposited and uriuency nitrogen of early feeding broilers were less than those of early fasting broilers (p<0.05) . The mortality rate of early feeding broilers was 8% less than that of early fasting broilers. 2. Compared to early fasting broilers , the index of spleen, bursa and thymus of early feeding broilers was higher (p<0.05) 3. The brisket ratio and net thorax ratio of early feeding were higher than that of early fasting broilers (p<0.05) . 4. Early fasting broilers had compensative growing.