甲醛处理菜籽饼对湖羊蛋白质利用效率和血浆游离氨基酸的影响

PROTEIN UTILIZATION EFFICIENCY AND BLOOD PLASMA FREE AMINO ACIDS CONCENTRATION IN HU-YANG SHEEP FED DIETS CONTAINING UNTREATED OR FORMALDEHYDE TREATED RAPE SEED MEAL

用甲醛分别按0.6％和0.8％(HCHO/粗蛋白)的配比处理菜籽饼(RSM)和豆饼(SBM),调制3种日粮。各日粮均以600g氨化稻草和200g混合精料为基础料,其蛋白质补充料分别为:(1)对照日粮(D-0):40gSBM加100RSM:(2)试验日粮-Ⅰ(D-Ⅰ):40gSBM加100g处理RSM;(3)试验日粮-Ⅱ(D-Ⅱ):40g处理SBM加100g处理RSM。各日粮的48小时瘤胃尼龙袋蛋白质消失率依次为80.03、75.91和70.49％。选用6只生长湖羊按3×3复拉丁方设计进行了氮平衡试验,并测定了晨饲前及其后1、3、6小时的瘤胃液NH_3—N浓度和空腹血浆游离氨基酸(FAA)、尿素含量。日粮D—Ⅰ的粗蛋白质消化率显著地高于D-0和D-Ⅱ日粮(P<0.01),而D-Ⅱ与D-0间没有显著差异(P>0.05)。日粮D-Ⅰ和D-Ⅱ与D-0相比,氮代谢率(沉积氮量/可消化氮摄入量)分别提高了25.57(P<0.05)和23.44％(P<0.05),氮沉积率(沉积氮量/摄入总氮量)分别提高了34.74(P<0.05)和23.78％(P>0.05),且D-Ⅰ略优于D—Ⅱ(P>0.05)。喂D—Ⅱ日粮的试羊的平均瘤胃液NH_3—N浓度显著低于喂D—0和D—Ⅰ日粮的试羊(P<0.01),而喂D—Ⅰ日粮的试羊略低于喂D—0试羊(P>0.05)。血浆尿素含量在各日粮组试羊间无显著差异(P>0.05)。各日粮的氨基酸(AA)组成基本一致,喂各日粮的试羊间血浆FAA浓度、必需AA/非必需AA以及甘氨酸/支链AA也没有明显差异(P>0.05)。上述结果表明,甲醛处理菜籽饼明显地改善了蛋白质的利用效率。

Six yearling Hu-yang sheep were used in a double 3x3 Latin square design to evaluate effect of formaldehyde treatment of rape seed meal (RSM) on protein utilization. Rape seed meal or soybean meal (SBM) were treated with formaldehyde at the rate of 0.6 or 0.8％ of crude protein (CP) respectively. All diets contained the same basal feed (600g ammonia bicarbonate-treated rice straw plus 200g concentrate mixture) and different protein supplements:(1) 100 g untreated RSM plus 40g untreated SBM(diet D-0); (2) 100g treated RSM plus 40g untreated SBM(diet D-Ⅰ) and (3) 100g treated RSM plus 40g treated SBM(diet D Ⅱ).The rates of disappearance of CP from nylon bag suspended in the rumen of sheep for 48 hr were 80.0,75.9,and 70.5％ for diet D-0, D-Ⅰ and d-Ⅱ, respectively. Apparent digestibility of CP was significantly higher for diet D-Ⅰ than that for diet D-0 or D-Ⅱ (P<0.01),with no significant difference between D-0 and D-Ⅱ (P>0.05). Proportion of nitrogen retention (NR) to the digestible N intake were 25.57(P<0.05) and 23.44％ (P<0.05) for diet D-Ⅰ and D-Ⅱ, higher than that for D-0 respectively. Proportion of NR tonitrogen intake (NR/NI) were 34.74(P<0.05) and 23.78％(P<0.05) for deiet D-Ⅰ and D-Ⅱ respectively, both higher than that for diet D-0, and NR/NI, value for diet D-Ⅰ slightly higher than D-Ⅱ (P<0.05). Average ammonia concentration in the rumen fluid was significantly lower for lambs given diet D-Ⅱ than those on diet D-0 or D-Ⅰ (P<0.01), with slightly lower concentration in lambs fed on D-Ⅰ than those on D-0 (P<0.05). The difference did not reveal statistical significance in the content of the blood plasma urea (P>0.05) and free amino acids (AA) (P>0.05) among lambs receiving different diets.No significant difference was found in ratios of essential to non-essential AAs, and of glycine to branched-chain AAs among lambs fed on different diets (P>0.05). It is inferred that the utilization efficiency of protein of rape seed meal can be greatly improved by treatment with formaldehyde.