| The study was conducted to find out whether the difference of available nutrients including apparent metabolisable energy(AME), true metabolisable energy(TME), apparent digestibility of amino acid (AAAD), true digestibility of amino acid (TAAD) and digestibility of fibre in plant feedstuffs for cockerel and drake existed. And it demonstrated the reasons by comparing digestion physiology and tissue anatomy of cockerel and drake. The study included four sections:Section 1: Comparative study of the digestibility of energy, amino acid, NDF and ADF in plant feedstuffs between cockerel and drakeIn this experiment, 48 Hy-Line Brown cockerels and 48 Peking drakes with the same weight and old (18 weeks) were employed to bioassay TME, TAAD and digestibility of fibre content of 10 plant feedstuffs, including paddy, corn grain, wheat grain, wheat bran, soybean oil, beef tallow, soybean meal, cottonseed meal, peanut meal and com starch. And every 8 cockerels and drakes were used to determinate one feedstuff.The results showed that there were significant differences of utilizing energy, amino acids and fibre of plant feedstuffs between cockerels and drakes (P<0.05,or P<0.01). Except ATM of cottonseed meal and corn starch and TME of cottonseed mea, AME and TME of the rest feedstuffs for drake were significantly higher than those for cockerels. The digestibility of most amino acids, fibre and all the total amino acid digestibility for drake were significantly higher than those for cockerels. During the period of 48-hour fecal collection, the amount of endogenous energy and amino acid in drakes was significantly higher than that of chicks, the effects varied with the method of collecting fecal. Therefore, the nutritional parameter of chick is not appropriate for duck.Section 2: Comparative study of the pH in digestive tract and digestive enzyme between cockerel and drake8 Hy-Line Brown cockerels and 8 Peking drakes with the same weight and old (18 weeks) were slaughtered after fasting 12hr to compare the pH in digestive tract and digestive enzyme between cockerel and drake.The results showed that the digestive tract content of cockerel and drake were acidity, and the pH value of intestine content was the highest and the stomach content was the lowest. The crop, caecum, glandular and stomach gizzard content pH value of drake were higher than those of cockerel. However, the mouth cavity, jejunum-ileum and rectum content pH value of cockerel were higher than those of drake.Pepsin, trypsin and chymotrypsin activities in digestive tract and digestive organ of drake were significantly higher than those of cockerel (p<0.05). Lipase activities in pancreas tissue of drake were significantly higher than those of cockerel (p<0.01). There were no significant differences of amylase and maltase activities in digestive tract content and digestive organ tissue between cockerel and drake. However, cellulase activities in digestive tract and digestive organ of drake were significantly higher than those of cockerel.Section 3: Comparative study of the clearance time and the passage rate of feed residues between cockerel and drakeA 2+7 factorial experiment was used to study the effects of animal (cockerel and drake) and removal period of digesta(4, 8, 14, 24, 32, 38, 48hr) on the residual amount of dry matter in digestive tract. 28 Hy-Line Brown cockerels and 28 Peking drakes with the same weight and old (18 weeks) were allotted randomly to 7 groups respectively, and every 4 cockerels and 4 drakes were slaughtered each period.The results indicated that the empting chyme in different part of the drake digestive tract were faster than that of cockerel. When removal period was 48h, there were more dry matters in drake digestive tract. Therefore, the collection time for cockerel was 32h and for cockerel was 48h.Section 4: Comparative study of the tissue structure of digestiveapparatus between drake and cockerelIn this experiment, 8 health Hy-Line cockerels and Peking drakes were slaughtered after fastin... |
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