An initial investigation replacing fish meal with a commercial fermented soybean meal product in the diets of juvenile rainbow trout

Abstract

The inclusion of PepSoyGen (PSG), a commercially-available fermented soybean meal product, was evaluated with juvenile rainbow trout, Oncorhynchus mykiss in an initial 70-day feeding trial, with a supplemental trial involving a subset of the experimental diets continuing for an additional 40 d. Six diets containing 0%, 10%, 20%, 30%, 40%, or 50% PSG, with the PSG directly replacing fish meal, were used in the first trial. There were no significant differences in weight gain or feed conversion ratio between the fish meal-based control diet and diets containing up to 30% PSG. However, weight gain was significantly reduced and feed conversion ratio significantly increased with the 40% and 50% PSG diets. No health assessment differences were observed in fish receiving any of the diets, and no evidence of gross gut inflammation was evident. There were no significant differences in weight gain or feed conversion ratio among the four dietary treatments ranging from 0% to 30% PSG which were fed for an additional 40 d after the initial 70-d trial (110 days total). Based on these results, juvenile rainbow trout diets can contain up to 30% PSG without any loss of rearing performance, thereby replacing at least 60% of the fish meal.

Comparative performance of two rainbow trout strains fed fermented soybean meal

“…Although the feed conversion ratios and HSI values in this study were higher than those reported in other rainbow trout feeding trials (Adelizi et al 1998;Cheng et al 2003a, b;Barrows et al 2008b), including those evaluating fermented soybean meal (Barnes et al 2012, the differences in study durations, fish sizes, and feeding levels make any comparisons among these studies problematic. The significantly elevated hepatosomatic index in the McConaughy strain may indicate increased fat deposition due to the slower growth rate and decreased feed efficiency than that observed with the Shasta strain (Takeuchi and Watanabe 1982).…”

“…Within each strain, the diet containing 15 % fish meal and 35 % fermented soybean meal produced similar growth results to the diet containing 40 % fish meal and no fermented soybean meal. This diet contains an increase in the amount of fermented soybean meal and a decrease in the amount of fish meal from the diet successfully used by Barnes et al (2012) during a feed trial with McConaughy strain rainbow trout. Using different fermentation techniques and substantial amino acid supplementation, Yamamoto et al (2010) were able to completely eliminate the fish meal in rainbow trout diets containing 47.6 % fermented soybean meal.…”

“…The Shasta strain was one of the first rainbow trout strains to be cultured, is very domesticated, and exhibits poor long-term survival in stocking programs (Needham and Means with different letters across a row are significantly different, and the absence of letters indicates no significant difference among the treatments (N = 4, P \ 0.05) a Condition factor (K) = 10 5 9 (weight)/(length 3 ) b Hepatosomatic index (HSI) = 100 9 (liver weight/body weight) c Viscerosomatic index (VSI) = 100 9 (viscera weight/body weight) d Fish health assessments rating system described in Barnes et al (2012) Behnke 1962; Vincent 1987; Barnes et al 2009). In contrast, the McConaughy strain is relatively difficult to culture and, unlike the Shasta strain, has shown the ability to survive, grow, and reproduce, after stocking into recreational fisheries containing predators and competitors (Barnes and Durben 2010;Davis et al 2013).…”

“…In addition to total tank measurements, five fish were randomly selected from each tank and individually weighed to the nearest grams and measured (total length) to the nearest millimeter at the trial beginning and end. At the end of the trial, fish health profiles, based on a modification of Goede and Barton (1990), Adams et al (1993) and Barton et al (2002), were completed using the score sheet described in Barnes et al (2012). Liver weights were recorded to the nearest milligram and the hepatosomatic index (HSI) determined using the formula: HSI (%) = 100 9 (liver weight/whole fish weight) (Strange 1996).…”

Traditional and Fermented Soybean Meals as Ingredients in Feeds for White Seabass and Yellowtail Jack

“…Barnes et al (2013) also reported that A. oryzae-B. subtilis-fermented soybean meal could be used to replace a moderate amount of dietary fish meal in feeds for Rainbow Trout Oncorhynchus mykiss, albeit with reduced growth performance and elevated food conversion ratio (FCR; Barnes et al 2012Barnes et al , 2013. These studies suggest fermentation may be equally or more effective than other, more costly processing strategies attempting to improve the acceptance and utilization of soy protein products in feeds for carnivorous fish.…”