CAJ | 학술논문

本试验旨在探讨脂肪和L-肉碱对大口黑鲈饲料中蛋白质的节约作用.采用3 × 2(蛋白质脂肪比×L-肉碱)完全随机设计,配制了不同蛋白质脂肪比(39.9%/7.4%、30.3%/13.9%和21.5%/19.5%)和L-肉碱水平(0和1 g/kg饲料)的6种等能饲料.选取平均初重为(3.27±0.21)g的大口黑鲈幼鱼270尾,随机分为6组(每组3个重复,每个重复15尾),随机饲喂1种饲料,试验期6周.结果表明:随着饲料中脂肪水平从7.4%升高到19.5%(蛋白质水平从39.9%下降到21.5%),鲈鱼的增重率从685%显著降低到176%(P<0.05),饲料效率从1.15增加到2.33(P<0.05),且投喂蛋白质脂肪比为21.5%/19.5%饲料的鲈鱼的肥满度显著低于投喂蛋白质脂肪比为39.9%/7.4%和30.3%/13.9%饲料的鲈鱼(P<0.05).投喂蛋白质脂肪比为21.5%/19.5%饲料的鲈鱼体水分含量显著低于投喂蛋白质脂肪比为39.9%/7.4%的饲料(P<0.05),且随着饲料中脂肪水平从7.4%升高到19.5%(蛋白质水平从39.9%下降到21.5%).全鱼脂肪含量从5.6%显著升高到11.5%(P<0.05),全鱼粗蛋白质含量从15.6%显著下降到10.4%(P<0.05).鱼体肝脏和肌肉中脂肪含量以及肝体指数在投喂蛋白质脂肪比为21.5%/19.5%饲料时达到最高值.此外,随着饲料中脂肪水平从7.4%升高到19.5%(蛋白质水平从39.9%下降到21.5%),淋巴细胞百分比由38.30%升高到48.41%(P<0.05),粒细胞百分比由51.75%下降到42.14%(P<0.05).由此得出,以节约蛋白质为目的的过量添加脂肪会导致鱼体生长速度降低,甚至引起脂肪肝的发生和机体免疫系统的应激反应.此外,饲料中添加1 g/kg的L-肉碱并不能提高大口黑鲈的生长性能,但蛋白质脂肪比和L-肉碱对淋巴细胞百分比和粒细胞百分比存在互作作用,并在饲喂添加1 g/kg L-肉碱的蛋白质脂肪比为21.5%/19.5%的饲料时达到峰值.
본시험지재탐토지방화L-육감대대구흑로사료중단백질적절약작용.채용3 × 2(단백질지방비×L-육감)완전수궤설계,배제료불동단백질지방비(39.9%/7.4%、30.3%/13.9%화21.5%/19.5%)화L-육감수평(0화1 g/kg사료)적6충등능사료.선취평균초중위(3.27±0.21)g적대구흑로유어270미,수궤분위6조(매조3개중복,매개중복15미),수궤사위1충사료,시험기6주.결과표명:수착사료중지방수평종7.4%승고도19.5%(단백질수평종39.9%하강도21.5%),로어적증중솔종685%현저강저도176%(P<0.05),사료효솔종1.15증가도2.33(P<0.05),차투위단백질지방비위21.5%/19.5%사료적로어적비만도현저저우투위단백질지방비위39.9%/7.4%화30.3%/13.9%사료적로어(P<0.05).투위단백질지방비위21.5%/19.5%사료적로어체수분함량현저저우투위단백질지방비위39.9%/7.4%적사료(P<0.05),차수착사료중지방수평종7.4%승고도19.5%(단백질수평종39.9%하강도21.5%).전어지방함량종5.6%현저승고도11.5%(P<0.05),전어조단백질함량종15.6%현저하강도10.4%(P<0.05).어체간장화기육중지방함량이급간체지수재투위단백질지방비위21.5%/19.5%사료시체도최고치.차외,수착사료중지방수평종7.4%승고도19.5%(단백질수평종39.9%하강도21.5%),림파세포백분비유38.30%승고도48.41%(P<0.05),립세포백분비유51.75%하강도42.14%(P<0.05).유차득출,이절약단백질위목적적과량첨가지방회도치어체생장속도강저,심지인기지방간적발생화궤체면역계통적응격반응.차외,사료중첨가1 g/kg적L-육감병불능제고대구흑로적생장성능,단단백질지방비화L-육감대림파세포백분비화립세포백분비존재호작작용,병재사위첨가1 g/kg L-육감적단백질지방비위21.5%/19.5%적사료시체도봉치.
A 3×2 (protein/lipid ratio× L-carnitine) factorial experiment was conducted to evaluate the protein sparing effect of lipid and L-carnitine in diets for largemouth bass, Micropterus salmoides. Two hundred and seventy fingerlings with aver-age body weight of (3. 27 ± 0. 21) g were randomly divided into six groups with 3 replicates each and fifteen fingerlings per replicate. Six isocaloric experimental diets were formulated with three protein/lipid ratios (39. 9%/7. 4% , 30. 3%/13. 9% and 21. 5%/19. 5%) crossing two L-carnitine levels (0 and 1 g/kg), and were fed to the fingerlings for six weeks. The results showed as follows: weight gain rate was 686% when fish were fed the 39. 9%/7. 4% (protein/lipid) diet but was reduced to 176% when fish were fed the 21. 5%/19. 5% diet (P<0. 05). Condition factor of fish fed 21. 5%/19. 5% (protein/lipid) diet was significantly lower than that of fish fed 39. 9%/7. 4% (protein/lipid) and 30. 3%/13. 9% (protein/lipid) diets (P<0. 05). FCR was increased significantly from 1.15 to 2. 33 when the dietary lipid level was increased from 7. 4% to 19. 5% (protein level was decreased from 39. 9% to 21. 5%) (P<0. 05). Body moisture content was lower in the fish fed 21. 5%/19. 5% than that in the fish fed 39. 9%/7. 4% diet (P<0. 05). When the dietary lipid level increased from 7. 4% to 19. 5% (protein level decreased from 39. 9% to 21. 5%) , the body crude lipid content increased from 5. 6% to 11. 5% while body crude protein content decreased from 15. 6% to 10. 4% (P<0. 05). The liver lipid, muscle lipid and hepatosomatic index reached the highest values when fish were fed 21. 5%/19. 5% (protein/lipid) diet. The percentage of lymphocytes was significantly increased from 38. 30% to 48. 41% (P<0. 05), and the percentage of granulocytes was significantly decreased from 51. 75% to 42.14% (P<0. 05) when dietary lipid level was increased from 7. 4% to 19. 5% (protein level was decreased from 39. 9% to 21. 5%). It was concluded that more dietary lipid addition with the aim to spare dietary protein slowed the growth of largemouth bass, and led to a fatty liver and immune suppression. Moreover, though the addition of 1 g/kg L-carnitine in diet had no effect on all the parameters tested relevant to fish growth performance, an interactive effect of dietary protein/lipid ratio with L-carnitine was observed in the percentages of granulocytes and lymphocytes with the peak values found in the fish fed 21. 5%/19. 5% (protein/lipid) and 0.1% L-carnitine diet.