Effect of Lactobacillus plantarum probiotic and different levels of soybean meal on growth and intestinal histomorphometry in rainbow trout diet

Dabbagh, Asal; Oraji, Hosein; Keramat Amirkolaie, Abdolsamad; Ansari, Zarbakht

doi:10.22124/janb.2022.22593.1173

Effect of Lactobacillus plantarum probiotic and different levels of soybean meal on growth and intestinal histomorphometry in rainbow trout diet

Document Type : Research Paper

Authors

¹ Department of Fisheries, Faculty of Animal Sciences and Fisheries, Sari Agricultural Sciences and Natural Resources University, Sari, Mazandaran, Iran

² Department of animal science, Faculty of animal science and fisheries, Sari Agricultural Sciences and Natural Resources University, Sari, Mazandaran, Iran

10.22124/janb.2022.22593.1173

Abstract

The present study was performed to examine the effects of probiotic addition to diet containing soybean meal (SBM) on growth and intestinal histomorphometry of rainbow trout. A total of 300 fry with mean initial weight of 20.05 ± 0.20 g were distributed to 12 tanks for 90 days. Experimental diets were included control (SBM 0 + probiotic 0), SBM 0 + probiotic 1, SBM 20% + probiotic 0, SBM 20% + probiotic 1, SBM 40% + probiotic 0 and SBM 40% + probiotic 1. On the 30^th day, the highest body weight increasing rate (BWI %) and specific growth rate (SGR) were observed in diet containing SBM 0 (0 and probiotic 1) and SBM 20% + probiotic. On the 60^th day, adding probiotic to SBM 0 and SBM 20% led to the highest BWI (p < 0.05). The lowest values of final weight, BWI (%) and SGR were achieved in SBM 40% without probiotic (p<0.05). Feed efficiency ratio was elevated in diets containing SBM 40% (p<0.05). On the 90^th day, final weight, final length and SGR were highest in fish fed SBM 0 (0 and 1 probiotic) and SBM 20% containing probiotic (p<0.05). According to intestinal histomorphometry, on the 60^th day, the highest villus height was found by supplementation of probiotic to SBM 0 (p<0.05). Epithelium thickness was significantly reduced by increasing SBM level to 40% (p<0.05). The greatest mucous thickness and goblet cells were observed in SBM 0 (0 and 1 probiotic) and SBM 20% containing probiotic groups (p<0.05). According to results on the 90^th day, villus height was significantly decreased by SBM level increasing (p<0.05). Epithelium thickness, mucous thickness and goblet cell in diet containing SBM 40% were lower than those in the other treatments (p<0.05). Considering present study, addition of probiotic to SBM 20% is beneficent to improve growth rate and intestinal histology.

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