How to Develop Strategies to Use Insects as Animal Feed: Digestibility, Functionality, Safety, and Regulation

Performance of Hermetia illucens (Diptera: Stratiomyidae) larvae reared on organic waste diets and pupal chitin and chitosan yield

Recently, much research has been oriented towards the influence of different food wastes and agricultural by-products on the final larval biomass and chemical composition of the insect species Hermetia illucens L. (Diptera: Stratiomyidae). However, there is a gap in the literature regarding the possible relationship between the feeding substrate of H. illucens larvae and chitin. In this context, in the present study, larvae of H. illucens derived from two populations (i.e., UNIPI and UTH), were reared on different diets composed of fruits, vegetables, and meat. Based on the results, the larval survival was high for all diets tested. Larval growth in terms of weight gain, larval length, and feed conversion ratio (FCR) depended on the composition of each diet. The chitin and chitosan composition of larvae, reared on different substrates, did not reveal significant differences. Given the fact that the feeding substrate represent a significant cost in the industrial production of insects, its correlation with a high value product (i.e. chitosan) is important. On the other hand, as the prepupal stage of H. illucens is currently used as animal feed, the metabolization of chitin by farmed animals when the larvae or prepupae were offered as feed could have adverse effects. Thus, depending on the final product that is to be produced, industries could benefit from the establishment of a suitable diet.

Effects of high doses of zearalenone on some antioxidant enzymes and locomotion of Tenebrio molitor larvae (Coleoptera: Tenebrionidae)

The mealworm Tenebrio molitor L. (Coleoptera: Tenebrionidae) feeds on wheat bran and is considered both a pest and an edible insect. Its larvae contain proteins and essential amino acids, fats, and minerals, making them suitable for animal and human consumption. Zearalenone (ZEA) is the mycotoxin most commonly associated with Fusarium spp. It is found in cereals and cereal products, so their consumption is a major risk for mycotoxin contamination. One of the most important effects of ZEA is the induction of oxidative stress, which leads to physiological and behavioral changes. This study deals with the effects of high doses of ZEA (10 and 20 mg/kg) on survival, molting, growth, weight gain, activity of antioxidant enzymes superoxide dismutase (SOD) and glutathione S-transferase (GST), and locomotion of mealworm larvae. Both doses of ZEA were found to (i) have no effect on survival, (ii) increase molting frequency, SOD, and GST activity, and (iii) decrease body weight and locomotion, with more pronounced changes at 20 mg/kg. These results indicated the susceptibility of T. molitor larvae to high doses of ZEA in feed.

Comparison study between single enzyme and multienzyme complex in distiller's dred grains with soluble supplemented diet in broiler chicken

Upregulation of the nutritional value of feed is the major target of various studies in the livestock industry, and dietary enzyme supplementation could aid in digesting the nondegrading nutrients of grains in feed ingredients. Dried distillers' grains with solubles (DDGS) is a byproduct of the fermentation process in the beverage industry and can be used as a large supply source of fiber in feed. Therefore, we conducted an experiment with male broiler chickens to investigate the effect of various types of enzymes on DDGS and compare the efficacy of single enzyme and multienzyme complexes on growth performance and gut environments in broiler chickens. We used 420 1-day-old broiler chickens (Ross 308), and they were allotted into 4 dietary treatments with seven replications (CON, corn-soybean meal [SBM] diet; NC, DDGS supplemented diet; SE, 0.05 % of mannanase supplemented DDGS-based diet; MC, 0.10% of multienzyme complex (mannanase and xylanase, glucanase) supplemented DDGS-based diet. The dietary exogenous enzyme in the DDGS-supplemented diet could improve growth performance as much as the growth of the control group, and digestibility of dry matter, crude protein, and gross energy were significantly increased by enzyme addition in groups of chicks fed DDGS-supplementation diet. Moreover, the populations of pathogenic bacteria, coliforms, and Bacteroidetes were significantly decreased by enzyme supplementation, which might lead to improved gut mucus-secreting cells and inflammatory cytokines in the jejunum. Collectively, dietary single enzyme and multienzyme complexes could improve gut environments, including intestinal immune responses and gut microbial population, and lead to improvement of growth performance in broiler chickens.

Effects of meal processing of black soldier fly on standardized amino acids digestibility in pigs

The aim of this study was to investigate the effect of incorporating black soldier fly (BSF) larvae and its processed form as an alternative source of protein to fish meal (FM) on the digestibility of amino acids (AA) in weaned pigs. Four cannulated pigs with an initial bodyweight of 13.25 ± 0.25 kg and aged 30 days were subjected to a 4 × 4 Latin square design with three treatments, as well as a nitrogen-free treatment. The diets used for each treatment consisted of a FM diet, a diet containing BSF larvae meal (BSFM), and a diet containing extruded BSF (BSFE). The study was conducted over four stages, with a total duration of 28 days. The apparent ileal digestibility (AID) of protein was higher in the FM treatment compared with the BSFM. Among essential AA, the AID of Arg, His, Leu, and Thr were higher in the FM compared with the BSFM and BSFE. A greater AID of Ile and Phe was observed in pigs in the FM treatment compared with the BSFM. The average AA digestibility did not show any difference between treatments. Among non-essential AA, the AID of Ala (p = 0.054) and Glu (p = 0.064) tended to be increased in the FM compared with the BSFM. Among essential AA, the standardized ileal digestibility (SID) of Arg, His, Ile, and Leu were higher in the FM compared with the BSFM. Among non-essential AA, the SID of Cys (p = 0.074) tended to be increased in the FM compared with the BSFM. In conclusion, the processing and thermal conditioning techniques utilized for BSF larvae meal showed a tendency for increased AA digestibility. Therefore, when formulating a diet, it is important to take into account the difference in AA digestibility between FM and BSFM.

Quality Characteristics of Black Soldier Flies Produced by Different Substrates

Black soldier fly (BSF; Hermetia illucens) has a high capacity for amino acids and fatty acid accumulation. This study was conducted to assess the effectiveness of tofu by-products, food waste, and vegetables for BSF growth and conversion efficiency. BSFs under tofu by-product treatments showed the greatest weight at d 12 and the harvest period. Moreover, BSF larval weight was greater in the food waste treatment compared with the vegetable treatment at d 12 and harvest. The larva yield result was greater in the vegetable treatment compared with the tofu by-product. The bioconversion rate was higher in the tofu by-product treatment compared with the food waste and vegetable treatments. The protein conversion rate and lipid conversion rate were the highest in the vegetable treatment. The protein yield and lipid yield were greatest in the tofu by-product treatment. The lauric acid content was increased in BSFs fed tofu by-products compared with the food waste treatment. The concentration of C16:1 was the highest in the tofu by-product treatment. The content of oleic acid and α-linolenic acid was higher in BSFs fed tofu by-products compared with the vegetable treatment. In conclusion, the tofu by-products show benefits for larval growth and nutrient accumulation, which can improve larval quality for livestock feed ingredients.

The Ingestion of Dietary Prebiotic Alternatives during Lactation Promotes Intestinal Health by Modulation of Gut Microbiota

Palm kernel expeller (PKE), a by-product of palm oil extraction, contains higher amounts of fiber than corn and soybean meal, but offers low energy density, protein value, and amino acid (AA) composition, limiting its use for swine. Recently however, it was reported that dietary fiber has a positive effect on the gut microbiota of the host, and therefore it is necessary to study the effect of PKE feeding on the intestinal microbiota of swine. In this study, we investigated the effects of supplementation with PKE in lactation diets on the gut microbiota composition of lactating sows and their litters. A total of 12 sows were randomly assigned to two dietary treatment groups in a completely randomized design. The treatments were a diet based on corn-soybean meal (CON) and CON supplemented with 20% of PKE. Sow and piglet fecal samples were collected before farrowing, on days 7 and 28 (weaning) after farrowing, and on days 7 and 28 (weaning) after farrowing, respectively, to verify gut microbiota composition by pyrosequencing analysis. The beta-diversity result showed a significant difference only in weaning-stage piglets, but dietary PKE altered the gut microbiota in sows by increasing the abundance of Lactobacillus compared with CON. In piglets, dietary PKE decreased the abundance of opportunistic pathogen Proteus and increased the abundance of potentially beneficial bacteria, such as Prevotellaceae and Prevotella. Our results can be helpful in developing feeding strategies and support the beneficial effects of dietary PKE to improve the gut health of animals.