The Effects Of Different Proteinous Feedstuff On Nitrogen Metabolism In Goat

Goats fitted with ruminal cannulae and duodenal cannulae were designed by 4×3Latin Square to study the effect of four diets comprised of different proteinfeedstuff(Alfafa hay, Leymus chinensis, Concentrate mix) on metabolic utilization ofnitrogen in gastrointestinal tract of goat.The results showed that:1.The apparent digestibility of nitrogen in C and D groups were 60.81 and61.24%,they were significant higher than group A(59.88%) and B(59.87%); Theretained nitrogen (RN) in C and D group(5.15,5.16g/d) was lower than A and B groups(P＜0.05).2.The concentration of ammonia-N(NH₃-N) and urea-N in the rumen with fourdiets were:16.42～29.82mg/100mL and 0.48～0.78mg/100mL, in duodenum were14.32～21.97mg/100mL and 0.09～0.20mg/100mL. But no significant differenceobserved statistically either in rumen or in duodenum among the four groups.3 The enrichment of total-¹⁵N, protein-¹⁵N in the rumen and duodenum wasdetected as the same order by D＞A＞C＞B, difference observed to some extent whilecomparing with D group and other groups, the enrichment of free amino acid- ¹⁵N inrumen in A,B,C group wre 0.849, 0.730, 0.746 and 0.926%, in duodenum theenrichment of free amino acid- ¹⁵N ranked by D＞A＞C＞B, and that in group D(0.043%)was much higher than that in group A(0.036%), B(0.030%) and C(0.035%) respectively(p＜0.05).4. The concentration of the ruminal FAA were 25.58～26.86mg/100mL, but nosignificant difference observed among the four treatments (P＞0.05), the concentration ofPAA in group A(22.82mg/100mL) was lower than that in group B(24.25 mg/100mL)and D(25.73 mg/100mL) respectively (P＜0.01), that in group B and C(23.53 mg/100mL)was lower than group D respectively(P＜0.05). 5. In the duodenum, the concentration of FAA and PAA in four groups were 33.37～33.93 mg/100ml, and 22.39～24.21 mg/100ml correspondingly, and there was nosignificant difference among groups(P＞0.05).Goats fitted with catheters in mesenteric and portal venous and carotid artery wereused as experimental animals. A 3×3 Latin Square experiment was carried out to studythe effect of different protein sources (soybean meal, cottonseed meal and DDGS) onmetabolism of protein and nitrogen in blood.The results showed that:1. The concentration of urea-N in artery were 10.44,11.53 and 7.87 mg.dl^-1,group Bhigher than A(P＜0.05),group A and B much higher than C(P＜0.01);in portal vein, groupA(8.95mg.dl^-1) and B(8.96 mg.dl^-1) significantly higher than C(7.07 mg.dl^-1)(P＜0.01);in mesenteric vein were 7.82～9.65 mg.dl^-1.No significant difference observed in amongthe three groups in mesenteric vein (P＞0.05).2. The enrichment of total-¹⁵N, protein-¹⁵N in artery were between 0.415～0.445%and 0.091～0.142%, and in portal vein were 0.402～0.436% and 0.075～0.129%. Therewas no significant difference for total-¹⁵N and protein-¹⁵N in artery, portal veinrespectively(P＞0.05), differences occurred in mesenteric vein to some extent, theenrichment of free amino acid-¹⁵N in portal was group C(0.033%) higher thanA(0.032%) and B(0.031%), and in mesenteric vein were 0.012,0.008 and 0.014%,groupB was lower than group A and C in mesenteric vein respectively(P＜0.05).3. The net flux of total-¹⁵N and protein-¹⁵N in PDV recorded no significantdifference among three groups (P＞0.05). Net flux of free amino acid-¹⁵N in groupA(4.589mg/d) was higher than that in group B(1.099mg/d) (P＜0.05), lower than that inC(5.068mg/d) group (P＜0.05). In MDV, C group was the highest(2.18mg/d) which wasmuch higher than that in group B(1.45mg/d) (P＜0.01)4. The concentration of FAA in the artery were 31.73, 27.90 and 35.06mg/100mlrespectively, great significant differences observed between A and C, A and Bgroups(P＜0.01);and in portal vein, group A much higher than B and C group(P＜0.01), inmesenteric vein, the concentration of FAA were 15.04,13.92 and 18.08mg/100mL, andgroup C higher than A and B(P＜0.01).The concentration of PAA in artery were43.59,39.62 and 43.17mg/100mL respectively, group B lower than A and C significantly(P＜0.05); in portal vein, the concentration of PAA were 34.91, 38.56 and 39.64 mg/100ml respectively, statistical analysis showed that group A higher than that ingroup B and C significantly; in mesenteric vein, C group(13.81 mg/100mL) was higherthan B group(10.74mg/100mL) significantly (P＜0.05).5.The absorption of FAA in 12h in portal vein were 194.47,190.70 and 275.75g,the absorption of PAA were 91.72,39.81 and 64.02g respectively.The net flux of freeamino acid/the absorption of FAA-N in PDV was group A(10.84g/d) much higher thanB(8.95g/d) and C(8.96g/d), and that were 17.67,14.68 and 20.37g/d in MDV, and groupB was lower than A and C group(P＜0.01).