Effect Of Different Starter Feeding Time On Absorption Of Yolk Sac And Growth And Development Of Yangzhou Gosling

This experiment was conducted to investigate effects of different starter feeding time on the absorption and utilization of yolk sac and the growth and development of gosling, and on the body sizes indexes and carcass characteristics of 10 week-old gosling. In order to determine the eligible starter feeding time of gosling, which will enrich the nutrition research of yolk sac period of gosling and provide some materials to goose-raising.A total of 480 Yangzhou goslings of similar weight which were born concentrated in 4 hours and health were selected and randomly assigned to four groups according to four feeding schedules (fasted for 12, 24, 36 and 48 h posthatch). Each group of 120 birds comprised of four replicate subgroups with 30 goslings per group comprising of 15 males and 15 females. After fasting, all birds were provided with feedstuff ad libitum until 70 d of age. At 12 h, 36 h, 60 h, 108 h, 156 h, 14 d, 21 d, 28 d and 70 d posthatch, 2 goslings (1 male and 1 female) per replicate of each experimental group were randomly selected and individually weighed, then got blood and dissected. Serum T3 was determined; before 156 hour-old, yolk sac was selected to weigh and dry to determine the percents of crude moisture, crude protein and crude fat; internal organ were taken out and weighed; duodenum, jejunal and ileum were taken out and made paraffin section for morphometrics, such as villus height, crypt depth and intestines wall thickness; feed consumption was recorded every day, and body weight were taken every week. The results indicated that:1 There was no significant effect of treatments (P>0.05) which were different in starter feeding time on yolk sac weight, the percents of crude moisture, crude protein and crude fat of yolk sac. But yolk sac weight, the percents of crude protein and crude fat of yolk sac of the group of fasted for 48 h were bigger than other 3 groups, the percents of crude moisture were smaller and the speed of absorption of yolk sac of the group of fasted for 24 h was the biggest. Nutrient substance in yolk sac was absorbed almost between 12-60 h posthatch, and more than 98% of yolk sac were absorbed at 156 h; during 12-60 h there were 85.50% of crude protein and 85.16% of crude fat of yolk sac been absorbed by the group of fasted for 24 h, but there were only 74.39% and 75.71% been absorbed by the group of fasted for 48 h. And the change of crude moisture of yolk sac was adverse to other nutritional ingredient. Compared with the change of crude protein and crude fat of yolk sac, the percents of crude fat were significant higher than crude protein of yolk sac (P<0.01) (except for 12 h).2 At 36 h the body weight of the groups of fasted for 36 h and 48 h were less than 12 h and began to increase after feeding. The body weight of the groups of fasted for 48 h were the least during 0-4 weeks. Feed conversion ratio was the least in the group of fasted for 48 h; the development of digestive organs and other organs (heart, liver and pancreas) in the group of fasted for 48 h were lower than other groups during 0-4 weeks. Spleen index decreased gradually after increasing to peak amplitude in 14 day, and the group of fasted for 24 h showed the trend of the highest value in 28 day among 4 groups. The time of bursa of Fabricius index got the highest value was imcompatible, the group of fasted for 12 h was at 14 d, the group of fasted for 24 h was at 7 d, the group of fasted for 36 h and 48 h were at 21 d. The change of concentration of serum T3 was wavy with growth, at 36 h the concentration in the groups of fasted for 36 h and 48 h was lower than other 2 groups (P<0.05).3 In all groups villus height of each stage of small intestine was smaller at 36 h than 12 h, after 36 h increased wavy; crypt depth increased between 12-108 h whether starter feeding or not and increased faster during this time; intestine wall thickness changed in wavy and increased anesis. Villus height, crypt depth, villus width and intestine wall thickness of the group of fasted for 48 h developed later than other groups, therefore it was concluded that it went against to increase body weight and play well in immunity performance.4 There was no significant difference of groups (P>0.05) which were different in starter feeding time on body weight in 5-10 weeks, but the speed of growth appeared faster at later growth stage in the group of fasted for 48 h, therefore the body weight of it was not the smallest at 10 week-old. There was no significant difference on feed consumption rate (P>0.05) in 5-10 weeks except that the group of fasted for 24 h was smaller than the group of fasted for 24 h at 8 week, and the group of fasted for 48 h got the biggest value at 9 week (P<0.05). There was no significant difference of treatments on weight of gizzard, small intestine, heart, liver, pancreas, spleen, bursa of Fabricius and length and organ morphous of small intestine at 10 week (P>0.05). But there were significant effects of starter feeding time on carcass characteristics (P<0.05), half net thorax percentage and whole net thorax percentage of the group of fasted for 48 h were smaller than the groups of fasted for 24 h and 36 h, however, abdominal fat percentage of the group of fasted for 24 h (P<0.05) was bigger. There was no significant difference on body steep length, keel length and shank length at 10 week(P>0.05), but chest width of the group of fasted for 24 h was bigger than the groups of fasted for 12 h and 48 h (P<0.05), and the body sizes indexes of the groups of fasted for 12 h and 48 h were smaller than other 2 groups.These results indicated that there were effects of starter feeding time on the growth and development of gosling, and the largest absorption speed of the nutrition in yolk sac was the group of fasted for 24 h, contrary the smallest was the group of fasted for 48 h. Therefor, this study suggested the better starter feeding time of gosling was 24-36 h poshatch.