Department of Basic Sciences and Aquatic Medicine, Faculty of Veterinary Medicine and Biosciences, Norwegian University of Life Sciences, Oslo, Norway.
Present Address: US Fish & Wildlife Service, Lamar, PA, 16848, USA.
BMC Vet Res. 2016 Sep 7;12(1):190. doi: 10.1186/s12917-016-0819-0.
The present study was undertaken to gain knowledge on the role of bile components and lecithin on development of aberrations in digestive functions which seemingly have increased in Atlantic salmon in parallel with the increased use of plant ingredients in fish feed. Post smolt Atlantic salmon were fed for 77 days one of three basal diets: a high fish meal diet (HFM), a low fishmeal diet (LFM), or a diet with high protein soybean meal (HPS). Five additional diets were made from the LFM diet by supplementing with: purified taurocholate (1.8 %), bovine bile salt (1.8 %), taurine (0.4 %), lecithin (1.5 %), or a mix of supplements (suppl mix) containing taurocholate (1.8 %), cholesterol (1.5 %) and lecithin (0.4 %). Two additional diets were made from the HPS diet by supplementing with: bovine bile salt (1.8 %) or the suppl mix. Body and intestinal weights were recorded, and blood, bile, intestinal tissues and digesta were sampled for evaluation of growth, nutrient metabolism and intestinal structure and function.
In comparison with fish fed the HFM diet fish fed the LFM and HPS diets grew less and showed reduced plasma bile salt and cholesterol levels. Histological examination of the distal intestine showed signs of enteritis in both LFM and HPS diet groups, though more pronounced in the HPS diet group. The HPS diet reduced digesta dry matter and capacity of leucine amino peptidase in the distal intestine. None of the dietary supplements improved endpoints regarding fish performance, gut function or inflammation in the distal intestine. Some endpoints rather indicated negative effects.
Dietary supplementation with bile components or lecithin in general did not improve endpoints regarding performance or gut health in Atlantic salmon, in clear contrast to what has been previously reported for rainbow trout. Follow-up studies are needed to clarify if lower levels of bile salts and cholesterol may give different and beneficial effects, or if other supplements, and other combinations of supplements might prevent or ameliorate inflammation in the distal intestine.
本研究旨在了解胆汁成分和卵磷脂在消化功能异常发展中的作用，这种异常似乎随着鱼类饲料中植物成分的增加而在大西洋鲑鱼中增加。将幼鲑鱼用三种基础日粮之一喂养 77 天：高鱼粉日粮（HFM）、低鱼粉日粮（LFM）或高蛋白豆粕日粮（HPS）。用 LFM 日粮通过补充以下物质制成另外五种日粮：纯化牛磺胆酸盐（1.8%）、牛胆汁盐（1.8%）、牛磺酸（0.4%）、卵磷脂（1.5%）或含有牛磺胆酸盐（1.8%）、胆固醇（1.5%）和卵磷脂（0.4%）的混合补充剂（suppl mix）。用牛胆汁盐（1.8%）或 suppl mix 从 HPS 日粮中补充另外两种日粮。记录鱼体和肠道重量，并采集血液、胆汁、肠道组织和食糜，以评估生长、营养代谢以及肠道结构和功能。
与 HFM 日粮相比，LFM 和 HPS 日粮喂养的鱼生长较少，血浆胆汁盐和胆固醇水平降低。对远端肠道的组织学检查显示，LFM 和 HPS 日粮组均有肠炎迹象，但 HPS 日粮组更为明显。HPS 日粮降低了远端肠道的食糜干物质和亮氨酸氨基肽酶的容量。膳食补充剂均未改善鱼类性能、肠道功能或远端肠道炎症的终点。有些终点反而表明存在负面影响。
一般来说，胆汁成分或卵磷脂的膳食补充并没有改善大西洋鲑鱼的性能或肠道健康终点，这与以前对虹鳟的报道形成鲜明对比。需要进一步研究以澄清胆汁盐和胆固醇水平降低是否会产生不同的有益效果，或者其他补充剂和其他补充剂组合是否可以预防或改善远端肠道的炎症。
