The mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) as a potential candidate to valorize crop residues

Abstract

Agricultural activities generate important amount of crop residues that need to be managed in appropriate way usingecofriendly and cost effective tools. The mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) is a potential candidate to valorize crop residues thatcan produce atthe same time an alternative feed based on insect larvae. Four crop residues (citrus, tomato, pepper and potato) mixedwith wheat bran (ratio 50:50) were evaluated as diets for mass rearing of T. molitor under controlled environmental conditions (T= 28 ± 1°C; RH=70 ± 5 % and total darkness). Five zootechnical parameters (weight gain, growth rate, mortality rate, weight of consumed feed and conversion rate) were adopted to evaluate thegrowth and life developmental traits of larvae during 45 days. The effect of crop residues used as diet had a significant impact on bothweight gain and growth rate. Importantly, crop residues used alone has a negative effect on all zootechnical parameters evaluated. Indeed, the amendment of wheat bran has a significant positive impact on these parameters. Citrus and tomato were the most toxic diets showing a mortality rate of 92 and 98 %, respectively. The most efficient diets werethe mixture of citrus residues andwheat branfollowed by the mixture of potato residues and wheat bran and the mixture ofpepper residues and wheat bran. Fed substrate had no impact on conversion rate.

Exploiting Agri-Food Waste as Feed for Tenebrio molitor Larvae Rearing: A Review

“…Roughly 4% of the tomatoes end up as waste after post-harvest processing [82]. Zim et al [83] decided to exploit the cultivation residues of tomatoes and include them in the diet of TM larvae in order to test their effect on growth and development. A combination of wheat bran (60%) and starter feed for broiler chickens (40%) was applied as a control diet, while tomato residue was used either as a complete feed or in combination with wheat bran (tomato residue 50% + wheat bran 50%).…”

“…Zim et al [83] also studied citrus residues besides tomato waste. The pulps, peels, seeds, and membrane citrus residues, which make up 40-60% of citrus fruits, collectively surpass approximately 110-120 million tons of waste annually [88].…”

“…Similar to other vegetables, after the potato is harvested, various residues are produced that remain unexploited [104]. Zim et al [83] used this residue as a substrate for feeding TM larvae, with the aim of creating a circular economy system. Two percentages of potato residues were tested: a 100% potato residue and a 50% potato residue, while a combination of wheat bran 60% and starter feed for broiler chickens 40% was used as a control sample.…”

“…In addition to potato residues, TM larvae were also tested for the same reason in pepper culture residue by Zim et al [83]. Two diets with pepper were used: 100% pepper residue and 50% pepper residue with 50% wheat bran.…”