Physical pretreatment procedures can significantly influence the quality of food and feed raw materials. To increase the ability to be digested in animals, cassava chips were pretreated by four alternative methods (extrusion, microwave irradiation, gamma irradiation, or NaOH hydrolysis), and then the chemical composition, physicochemical properties, and in vitro digestibility of the pretreated samples were assessed and compared with unprocessed cassava chips (control). The chemical compositions (crude protein, ether extract, neutral detergent fiber, acid detergent fiber, ash, non-fiber carbohydrate, and gross energy) were significantly altered due to the pretreatment methods (p < 0.05). The nutritive profile was qualitatively changed when assessed through Fourier-transform infrared spectroscopy. Some physicochemical properties in association with enzymatic hydrolysis, which include pH, water solubility, water absorption capacity, thermal properties (differential scanning calorimetry), diffraction pattern (X-ray diffractometry), and microstructure (scanning electron microscopy), were significantly changed. In vitro carbohydrate digestibility based on digestive enzyme extracts from Nile tilapia (Oreochromis niloticus) suggests the microwaving method for cassava chips preparation, while microwaving, followed by extrusion or gamma irradiation, was suggested for broiler (Gallus gallus domesticus). There were no differences in the pepsin-cellulase digestibility values tested for the ruminant model. These findings suggest the use of pretreated cassava chips in animal feeding.

Mealworms ( Tenebrio molitor ) are edible insects typically used as feed for captive reptiles, fish and birds. However, the incorporation of mealworm feed substrate waste (FSW) in fish feed has not been fully investigated. The objective of this study was to evaluate the nutritional composition and in vitro digestibility of mealworm FSW. Mealworm larvae were reared on a substrate of commercial chicken feed. Triplicate samples ( ) of FSW were harvested on days 0 (0FSW), 7 (7FSW) and 14 (14FSW). The proximate chemical compositions of the three substrates were statistically different ( ). The FSW exhibited changes in proximate chemical composition, nutritional profile, and physicochemical properties that were related to the time of harvesting. Crude protein, crude fiber, and crude ash contents increased with time while ether extract, nitrogen-free extract, and gross energy decreased ( ). Fourier transform infrared spectrometry indicated some modifications in the nutritive profile of the FSW, and the pH, water solubility, water absorption capacity, microstructure, thermal characteristics and secondary protein structures changed. In vitro protein digestibility (IVPD) was highest in 7FSW in response to Nile tilapia ( Oreochromis niloticus ) digestive enzymes, and highest in 14FSW in response to striped catfish ( Pangasianodon hypophthalmus ) enzymes ( ). The IVPD values were generally lower than those of commercial fish feeds or commercial feed ingredients ( ). Our findings suggest that mealworm FSW could be included in aquafeed as an alternative protein source.

Microwaving has been used to qualitatively improve feed ingredients prior to including them in cattle feed. However, it is not known whether feed ingredients should be microwaved separately or in a mixture before being included in cattle feed concentrates. In the current study, the effects of the partial and full microwaving of high starch ingredients were investigated regarding their impact on the nutritional composition, physicochemical properties, and in vitro digestibility of feed concentrates. The cassava was microwave-irradiated before being mixed with other ingredients (MC, 35% of formulation). A microwave-cooked cassava–corn meal mixture (MCC, 45% of formulation) and a combination of all solid components (MSI, 96% of formulation) were also compared. A feed containing non-microwaved ingredients was formulated and served as the control (NM). Significantly altered proximate compositions and nutritive profiles were observed in all the microwaved components (p < 0.05). The observed modifications in pHs, water absorption capacities, thermal properties (differential scanning calorimetry), diffraction patterns (X-ray diffractometry), and microstructures (scanning electron microscopy) indicated enhanced enzymatic hydrolysis in vitro. A higher cellulase organic matter solubility and digestible organic matter were observed in the MCC and MSIs feeds relative to the control NM (p < 0.05). These findings indicate a combination of components could be added to feedstock before it is microwave processed to potentially include this pretreatment in the feed production process.

Black soldier fly larvae (BSFL, Hermetia illucens) are an alternative source of protein whereas little research has yet been conducted to investigate the potential application of feed substrate waste (FSW) from larval production in aquaculture. The nutritive value and physicochemical properties of FSW from BSFL were here investigated in vitro. Ten-day-old first-instar larvae were cultivated on two feed substrates: laying hen feed (FS I) or a laying hen feed-rice bran blend (1:1 w/w, FS II). FSW samples were collected at day 4.5 (0.5FSW) and day 9 (1FSW) of larval rearing, and compared to the original feed substrate (0FSW). Crude protein increased depending on FS type, harvesting time (HT), and their interaction. Crude lipid, crude fiber, acid detergent fiber, neutral detergent fiber, crude ash, nitrogen-free extract, and gross energy decreased (). Analysis of the physicochemical properties of FSW by various techniques (scanning electron microscopy, differential scanning colorimetry, X-ray diffractometry, and Fourier transform infrared spectroscopy) revealed qualitative and quantitative changes in FSW, driven by biological processes of BSFL. The digestibility of protein in FSW was determined by an in vitro protein digestibility (IVPD) test using crude digestive enzyme extracts from Nile tilapia (Oreochromis niloticus) and striped catfish (Pangasianodon hypophthalmus). 1FSW from FS I showed significantly better availability of protein relative to 0.5FSW (), while the IVPD of FSW from FS II was stable () or reduced (). Findings from this study suggest FSW from BSFL cultivation could be a protein source in aquafeed.

Ornamental fish shipped by road or rail may spend days in transit without food, leading to a reduction in somatic growth after transportation and during acclimatization. In the present study, a time-series (0, 2, 4, 6, 8, 10, and 12 days) experiment was conducted to investigate the growth recovery of male Siamese fighting fish (Betta splendens, 1.56 ± 0.02 g body weight, n = 15 per group) transported by road for two days. Biometric changes, nesting activity, skin pigmentation, digestive enzyme activity, muscle quality, and whole-body composition, were compared across all fish groups. The recovery in growth, as indicated by final body weight, increased with post-transportation time (p < 0.05), causing a significant reversal of weight loss with a proportionally stable condition factor from day 8 until the end of observation (p > 0.05). During this time period, the fish exhibited similar bubble-nest building activity to the control group that was not transported (p > 0.05). Color parameters, digestive enzyme activities, muscle quality, and whole-body composition of fish 8 days after shipping were comparable to the control fish group (p > 0.05). Our findings indicate that an 8-day recovery time is an appropriate protocol for Siamese fighting fish acclimatization following overland shipping.