Tayyaba Maria, Fatima Mahroze, Shah Syed Zakir Hussain, Khan Noor, Ali Wazir, Riaz Muhammad Nouman
University of Veterinary and Animal Sciences, Lahore, Pakistan.
Department of Zoology, University of Gujrat, Gujrat, Pakistan.
J Anim Physiol Anim Nutr (Berl). 2024 Jan;108(1):27-35. doi: 10.1111/jpn.13863. Epub 2023 Jul 21.
The aim of this study was to determine the optimal dietary phosphorus (P) requirement and its effects on growth performance, body composition, mineralization and alkaline phosphate (ALP) activity in silver carp (Hypophthalmichthys molitrix). A total of 360 fish with an average initial weight of 7.0 ± 0.15 g were divided into 18 tanks (70 L capacity each) with a stocking density of 20 fish per tank in triplicate. The fish were fed diets containing six levels of P (3.3, 4.4, 5.5, 6.5, 7.5 and 8.6 g/kg) up to satiation for 90 days twice daily at 09:00 and 16:00. The results showed that fish fed diets containing 6.5 and 7.5 g/kg dietary P had significantly higher (p < 0.05) growth performance in terms of final weight gain, average weight gain (AWG), weight gain% (WG%), protein efficiency ratio (PER) and specific growth rate (SGR) than fish fed other diets. The best value of the feed conversion ratio (FCR) was observed in fish fed the 6.5 g/kg P diet, which was not significantly different from the 7.5 g/kg P diet. Increasing P supplementation above 6.5 g/kg significantly reduced (p < 0.05) the feed intake of silver carp. Whole-body composition analysis indicated that increasing P levels resulted in a decrease (p < 0.05) in crude fat (CF) and an increase (p < 0.05) in crude ash (CA) content, while crude protein (CP) and moisture content remained unaffected (p > 0.05). Fish fed diets containing ≥6.5 g/kg P had significantly higher (p < 0.05) Ca content in the whole body, bones and scales compared to those fed diets containing ≤5.5 g/kg P. A similar trend was observed for P and Mg contents in the whole body, bones and scales. The Zn content tended to decrease (p < 0.05) with increasing P supplementation in the whole body and bones, but fish fed diets containing ≥6.5 g/kg P had significantly higher (p < 0.05) Zn content compared to fish fed diets containing ≤5.5 g/kg P. The Ca/P ratio was significantly affected by P supplementation. Fish fed diets containing ≥6.5 g/kg P had significantly higher (p < 0.05) Ca and P contents in the serum than fish fed other diets. ALP activity increased (p < 0.05) with increasing P levels up to 6.5 g/kg P and decreased (p < 0.05) thereafter. In conclusion, supplementing P up to 6.35 g/kg is recommended for the optimal growth of silver carp.
本研究旨在确定鲢鱼（Hypophthalmichthys molitrix）的最佳日粮磷（P）需求量及其对生长性能、身体组成、矿化作用和碱性磷酸酶（ALP）活性的影响。总共360尾平均初始体重为7.0±0.15克的鱼被分成18个水箱（每个水箱容量70升），每个水箱放养密度为20尾鱼，共设三个重复组。每天09:00和16:00给鱼投喂含六种磷水平（3.3、4.4、5.5、6.5、7.5和8.6克/千克）的日粮，直至饱食，持续90天。结果表明，就末体重增加、平均体重增加（AWG）、体重增加百分比（WG%）、蛋白质效率比（PER）和特定生长率（SGR）而言，投喂含6.5和7.5克/千克日粮磷的鱼比投喂其他日粮的鱼具有显著更高（p<0.05）的生长性能。在投喂含6.5克/千克磷日粮的鱼中观察到最佳饲料转化率（FCR）值，该值与含7.5克/千克磷日粮的鱼没有显著差异。日粮磷添加量超过6.5克/千克会显著降低（p<0.05）鲢鱼的采食量。全身成分分析表明，磷水平升高导致粗脂肪（CF）含量降低（p<0.05），粗灰分（CA）含量增加（p<0.05），而粗蛋白（CP）和水分含量不受影响（p>0.05）。与投喂含≤5.5克/千克磷日粮的鱼相比，投喂含≥6.5克/千克磷日粮的鱼全身、骨骼和鳞片中的钙含量显著更高（p<0.05）。全身、骨骼和鳞片中的磷和镁含量也观察到类似趋势。随着日粮磷添加量增加，全身和骨骼中的锌含量趋于降低（p<0.05），但与投喂含≤5.5克/千克磷日粮的鱼相比，投喂含≥6.5克/千克磷日粮的鱼锌含量显著更高（p<0.05）。钙磷比受日粮磷添加量的显著影响。与投喂其他日粮的鱼相比，投喂含≥6.5克/千克磷日粮的鱼血清中的钙和磷含量显著更高（p<0.05）。ALP活性在磷水平升高至6.5克/千克时增加（p<0.05），此后降低（p<0.05）。总之，建议日粮磷添加量至6.35克/千克以实现鲢鱼的最佳生长。
