Effects of fishmeal replacement by Tenebrio molitor meal on growth performance, antioxidant enzyme activities and disease resistance of the juvenile pearl gentian grouper (Epinephelus lanceolatus ♂ × Epinephelus fuscoguttatus ♀ )

Abstract

A 50-day feeding trial was conducted for juvenile pearl gentian grouper (Epinephelus lanceolatus ♂ 9 Epinephelus fuscoguttatus ♀) to determine the optimal amount of Tenebrio molitor meal (TM) that could replace fishmeal (FM) in feeds without reducing growth performance, antioxidant enzyme activities and resistance. Six isonitrogenous and isolipidic diets were formulated with TM replacing 0% FM respectively. Each diet was randomly divided into triplicate groups with 30 juveniles (initial weight 6.60 AE 0.00 g). After feeding trail, fish were challenged by Vibrio harveyi for 7 days.The results showed that each treatment had better survival rate between 96.67% and 100%. Fish fed with control and T6 diet showed lower final weight and weight gain rate as compared to other diets. The feed conversion ratio of fish fed on T12 and T18 diet had no significant difference compared to control diet. As compared to control diet, other diets had no significant differences on specific growth rate and temperature growth coefficient. Fish fed with T6 diet had highest liver glutathione reductase activities. No significant differences were observed in liver superoxide dismutase activities in fish fed with T6, T12, T25, T31 and control diet.Fish fed on T18 diet had lowest hepatic malondialdehyde contents and a highest relative per cent survival. According to a broken-line model, the recommended substituted ratio of TM for FM was estimated to be 12.3% for grouper obtaining maximum WGR, corresponding to additive amount of TM is 4.92%.

Replacement of Fish Meal by Defatted Yellow Mealworm (Tenebrio molitor) Larvae in Diet Improves Growth Performance and Disease Resistance in Red Seabream (Pargus major)

“…In addition to the results with other insect species mentioned above, the dietary intake of MW is known to have immunostimulating activity in fish [15,16,17]. Moreover, a 7.5% MW inclusion was reported to enhance Vibrio harveyi resistance in juvenile pearl gentian grouper [12]. Although they concluded that chitin in MW could enhance the immune response in fish, the mechanism is still unknown.…”

“…Although this insect appears to possess adequate amino acid profiles for use in fish feed [1,2,3,5,6], reports on the successful complete substitution of fish meal (FM) with MW have been limited. Based on the evidence published to date, a diet with 50% to 70% replacement of FM with dried full-fat mealworm larvae resulted in similar growth to the FM diet in gilthead seabream ( Sparus aurata ) [7], European seabass ( Dicentrarchus labrax ) [8], black spot seabream ( Pagellus bogaraveo ) [9], and rainbow trout ( Oncorhynchus mykiss ) [10,11], and only 12% replacement for FM was achieved with defatted mealworm larvae in pearl gentian grouper ( Epinephelus lanceolatus × Epinephelus fuscoguttatus ) [12]. However, the MW’s potential in diets for red seabream ( Pagrus major Temminck and Schlege) (Perciformes: Sparidae) has not been investigated.…”

“…A low inclusion of housefly ( Musca domestica ) pupae increased phagocytic activity and disease resistance against Edwardsiella tarda in red seabream ( Pargus major ) [14]. Dietary inclusion of MW is also known to increase the enzyme activities of the immune systems of European seabass [15], rainbow trout [16], mandarin fish ( Siniperca scherzeri ) [17], and pearl gentian grouper [12].…”

Animals Fed Insect-Based Diets: State-of-the-Art on Digestibility, Performance and Product Quality

“…However, few studies are available on the use of a defatted TM meal. On juvenile pearl gentian grouper, Song et al [42] tested a TM meal with a 65% CP content in a feeding trial that lasted 50 days. The fish were fed up to 31.5 % of graded levels of TM meal and the authors found a lower final weight and WG rate in the control fish and in the 6.25% inclusion level groups, while the FCR of the fish fed 12.5 and 18.75% TM diets showed no significant difference compared to the control diet.…”

“…The fish were fed up to 31.5 % of graded levels of TM meal and the authors found a lower final weight and WG rate in the control fish and in the 6.25% inclusion level groups, while the FCR of the fish fed 12.5 and 18.75% TM diets showed no significant difference compared to the control diet. In order to obtain a maximum WG rate and according to a broken-line model, authors recommended a TM inclusion level of 4.92%, corresponding to a FM substitution of 12.3% [42].…”