Crude protein in low‐fish meal diets for juvenile Litopenaeus vannamei can be reduced through a well‐balanced supplementation of essential amino acids

Abstract

The use of supplemental essential amino acids (EAAs) has been shown to provide an opportunity to minimize excess levels of crude protein (CP) in animal feeds. The present study investigated the effect of reducing the amount of CP in low‐fish meal diets (5%) for juvenile Litopenaeus vannamei. Four sets of diets were prepared containing (% on a fed basis, mean ± SD) 31.24 ± 0.71, 33.70 ± 0.41, 36.90 ± 0.44, and 39.63 ± 0.14% CP, with each protein level containing a total dietary methionine (Met) (Met + Cys) level of 0.56 ± 0.02 (1.07 ± 0.23), 0.71 ± 0.01 (1.22 ± 0.20), 0.88 ± 0.02 (1.38 ± 0.22), or 1.04 ± 0.02% (1.55 ± 0.18%). Shrimp of 1.00 ± 0.08 g were stocked in 84 outdoor tanks of 1 m3 at a rate of 100 shrimp/m2 and raised for 75 days. Final survival ranged from 83 to 97% and was unaffected by Met content. Both survival and yield were significantly depressed when shrimp were fed the 31% CP diet. Shrimp grew at a weekly rate of between 0.79 and 0.97 g, achieving a final body weight (BW) in excess of 10.8 g. There was a significant interaction between CP and Met over BW. Shrimp fed 0.56% Met achieved the lowest BW at harvest. Increasing CP beyond 34% did not enhance BW. With a dietary Met content of 0.71%, the highest BW was achieved with 34% CP compared to other levels. There was a significant improvement in Feed Conversion Ratio (FCR) when CP was raised from 31 to 34%. Similarly, dietary Met levels above 0.71% resulted in a significantly better FCR compared to 0.56%. Our study has shown that, if dietary Met (Met + Cys) meets a minimum of 0.71% (1.22%), levels of CP could be reduced from 40 to 34% without adverse effects on shrimp performance.

Growth performance, apparent digestibility coefficients and digestive enzyme activities of Pacific white shrimp, Penaeus vannamei fed low fishmeal diets supplemented with DL‐methionine and phytase

“…In the present study, a low fishmeal diet supplemented with DLmethionine (SPC 2) and DL-methionine and phytase (SPC 4) resulted in improved growth performances than the other diets, indicating that DL-methionine supplementation is required to meet the methionine requirement of P. vannamei in the low fishmeal diet containing soy protein concentrate-soybean meal. The result of Nunes et al (2019), is in accordance with our present study, where higher body weight was achieved in P. vannamei with a dietary methionine level of 7.1 g/kg. Replacing fishmeal with soybean meal and a higher inclusion level of SPC without any dietary amino acid supplementation tends to reduce the growth rate of shrimp (Mohd Faudzi et al, 2018;Sookying & Davis, 2012;Zhang et al, 2018).…”

“…Survival was not significantly affected (p > .05) by the dietary inclusion of DL-methionine, phytase and their combination, indicating that they were unrelated to the experimental diet. The lowest FCR recorded in the diets supplemented with DL-methionine in the present study are in line with the studies of Lim and Dominy (1992) and Nunes et al (2019), where improvement in feed intake, FCR and growth of P. vannamei were observed in the groups supplemented with amino acids.…”

Feed preference and growth response of juvenile Litopenaeus vannamei to supplementation of marine chemoattractants in a fishmeal‐challenged diet

“…Therefore, in agreement with previous studies, there is no clear indication that enhanced growth could have been driven by an increased dietary supply of these nutrients. Dietary EAA composition in our study, including Met + Cys, likely met minimum levels to optimize the growth of whiteleg shrimp under green‐water rearing systems (Façanha, Oliveira‐Neto, Figueiredo‐Silva, & Nunes, ; Nunes, Sabry‐Neto, & Masagounder, ). On the other hand, restricting fishmeal inclusion to 3% with only 2.66% fish oil in the NEG control diet may have impacted the supply of long‐chain polyunsaturated fatty acids (LC‐PUFAs), particularly eicosapentaenoic (EPA, 20:5n‐3) and docosahexaenoic (DHA, 22:6n‐3) acids.…”

Retrospect of fish meal substitution in Pacific white shrimp (Litopenaeus vannamei) feed: Alternatives, limitations and future prospects

“…11 For example, increasing the feed protein concentration from 31% to 34% in the presence of methionine deficiency (<0.56% of feed) failed to increase weight gain of shrimp; in contrast, when methionine content of diet was increased above 0.71%, shrimp fed a diet with 34% protein showed similar growth and feed conversion ratio compared with that fed diet of 40% crude protein content. 123 Besides, in bioflocdominated production systems, feed protein could be decreased without affecting production of shrimp as long as the EAA requirement of shrimp is met, indicating that amino acid profile may stand in a more important position in the feed than crude protein content, based on meeting the minimum protein requirements of shrimp. 124 On the other hand, the function of supplementing non-essential amino acids (NEAAs) in shrimp feed has also received attention.…”