投喂皇竹草和配合饲料对草鱼生长及肌肉营养成分的影响

为探究短期内投喂优质牧草对大规格草鱼生长及肌肉营养成分的影响,分别以皇竹草、配合饲料在半径为5 m的圆形室内水泥池中饲养初始体质量为(2.0±0.1)kg的草鱼Ctenopharyngodon idellus(分别记为牧草组与配合饲料组),每天于8:30和16:30投喂两次,试验时间为3个月,试验结束时对其生长、体型和肌肉营养成分等指标进行了测定。结果表明:牧草组草鱼的增重率、肥满度、脏体指数和肝体指数均显著低于配合饲料组(P0.05),而空壳率显著高于配合饲料组(P0.05);两组草鱼肌肉中普通营养成分、矿物元素和氨基酸含量均无显著性差异(P0.05),除月桂酸外其余脂肪酸含量均无显著性差异(P0.05);牧草组和配合饲料组草鱼氨基酸组成基本一致,均含有16种氨基酸,氨基酸总量分别为19.53%和19.33%;牧草组必需氨基酸指数为83.85,配合饲料组必需氨基酸指数为83.67,其组成均符合FAO/WHO的标准;牧草组与配合饲料组草鱼肌肉中均含有19种脂肪酸,其中主要脂肪酸为棕榈酸、油酸和亚油酸,∑n-3 PUFA/∑n-6 PUFA值分别为25.80%和22.56%。研究表明,与配合饲料组相比,在不降低肌肉营养物质含量前提下,摄食牧草的草鱼具有出肉率高、体型好等优点,更符合商品鱼市场要求。

Effects of hybrid giant napier Pennisetum sinese Roxb and formulated feed on growth and nutrient compositions in muscle of grass carp Ctenopharyngodon idellus

Grass carp Ctenopharyngodon idellus with body weight of (2.0±0.1)kg were reared in a circular indoor cement pool with a radius of 5 meters and fed separately extruded feed and diet containing hybrid giant napier (Pennisetum sinese Roxb) with triplication to investigate the improved effect of dietary hybrid giant napier on growth and nutrient compositions in muscle of grass carp. The results showed that there were significantly lower weight gain rate,condition factor,viscera-somatic index and hepato-somatic index in the grass carp fed the diet containing hy-brid giant napier than in the fish fed the formulated feed (P<0.05), with significantly higher ratio of eviscerated body weight to total body weight in the grass carp fed the diet containing hybrid giant napier than in the fish fed the formulated feed(P<0.05). There were no significant differences in approximate composition,mineral elements,a-mino acids and fatty acids(except for lauric acids) in muscle between the fish fed the formulated feed and the fish fed the diet containing hybrid giant napier (P>0.05). There were almost the same amino acids composition inclu-ding 16 amino acids in grass carp in the two groups,accounting for 19.53% and 19.33%, respectively. The grass carp fed the diet containing hybrid giant napier had the essential amino acid index of 83.85 and the fish fed the for-mulated feed had the essential amino acid index of 83.67, within the FAO/WHO standards. Nineteen fatty acids, primarily palmitic acid,oleic acid and linoleic acid,were found in muscle of the grass carp fed the two diets,with∑n-3 PUFA /∑n-6 PUFA ratio of 25.80% in the fish fed the diet containing hybrid giant napier and 22.56% in the fish fed the formulate diet. The findings indicated that the grass carp fed the diet containing hybrid giant napier had higher dressing rate and better body type than the fish fed the formulate diet did, corresponding with the de-mand of commodity market.