Effects of the Replacement of Dietary Fish Meal with Defatted Yellow Mealworm (Tenebrio molitor) on Juvenile Large Yellow Croakers (Larimichthys crocea) Growth and Gut Health

Abstract

This study was conducted to investigate the effects of Tenebrio molitor meal (TM) replacement for fish meal (FM) on growth performance, humoral immunity, and intestinal health of juvenile large yellow croakers (Larimichthys crocea). Four experimental diets were formulated by replacing FM with TM at different levels—0% (TM0), 15% (TM15), 30% (TM30), and 45% (TM45). Triplicate groups of juveniles (initial weight = 11.80 ± 0.02 g) were fed the test diets to apparent satiation two times daily for eight weeks. There was no significant difference in final body weight (FBW) and weight gain rate (WG) among TM0, TM15, and TM30, while TM45 feeding significantly reduced the FBW and WG. Compared with TM0, AKP activity in serum was significantly decreased in TM45, while the TM15 group remarkably increased LZM activity. TM30 showed significantly higher serum C3 levels compared to the TM0 group, while the TM addition groups decreased the C4 levels significantly in the serum. In terms of intestinal histology, the addition of TM increased the height and thickness of the intestinal villus and also increased the thickness of the intestinal muscles significantly. The addition of TM significantly reduced the serum DAO and D-lactate concentrations. The results of 16S rRNA gene sequencing showed that the addition of TM significantly enhanced the relative abundance of Bacilli and Lactobacillus and contributed to the decrease in the relative abundance of Plesiomonas. In addition, the TM30 and TM45 groups significantly reduced the abundance of Peptostreptococcaceae. Overall, our results indicated that TM could be a viable alternative protein source, 6.7% TM supplantation (replacing 15% FM) in large yellow croaker feed improved humoral immunity and intestinal health with no adverse effects on growth. Furthermore, the replacement of FM with 30% and 45% TM adversely affects growth and humoral immunity.

Improving Yellow Mealworm (Tenebrio molitor) Utilization with Sodium Butyrate in Nile Tilapia Diets: Effects on Growth Performance, Intestinal Histology, Antioxidative Response, and Blood Biomarkers

“…Nile tilapia is a vital finfish species consumed by humanity around the globe, associated with their suitability for diverse environmental conditions and acceptability for different feeding regimes [34,35]. Yellowworm meal has been approved as a suitable replacement for FM in aquafeed [23,24]. In addition, sodium butyrate (SB), a functional organic acid, is involved in enhancing digestive system health and, thereby, the entire fish body's performance [52].…”

“…Interestingly, tilapia-fed T. molitor or FM with SB addition showed higher growth performance and improved FCR and PER than tilapia without SB addition. The lack of growth performance of tilapia-fed T. molitor without SB can be related to chitin, which acts as an antinutritional factor leading to low digestion capacity of fish intestines [23,24]. The low digestibility of high inclusion levels of T. molitor may also result from the lack of micronutrients and the possibility of toxin 1,4-benzonchinone formation [53].…”

“…Yellow worms replaced up to 75% of FM without interrupting the growth performance and health status of several carnivorous, omnivorous, and herbivorous fish species [22]. However, a high inclusion rate of yellow worm meal in aquafeed may interrupt intestinal health and lead to low feed utilization, irregular metabolic rate, and retarded growth performances [23,24]. Thus, it is crucial to investigate several feeding strategies to accommodate the optimum inclusion levels of insect meals without affecting fish performances [1,25].…”

Addressing Phosphorus Waste in Open Flow Freshwater Fish Farms: Challenges and Solutions

“…Apart from the nutritional parameters, phosphorus absorption in farmed fish is influenced by several factors, including water temperature and fish size [101]. Temperature in open flow fish farms can vary seasonally, but other factors, such as fish size, feeding regimes, and water flow, may also change, contributing to a range of interactions affecting phosphorus release from freshwater open flow fish farms.…”

A Review on the Use of Azolla Meal as a Feed Ingredient in Aquatic Animals’ Diets

“…As such, alternative protein sources in aquafeed have become a hotly debated topic in the industry. With the high cost and limited availability of traditional animal proteins like fishmeal, feed formulations have shifted toward plant-based proteins [8,9]. Plant proteins such as soybean meal, wheat gluten meal, cotton meal, and distillers dried grain with solubles have been found to be effective substitutes for fishmeal in fish diets [10,11].…”