Subchronic Exposure to Polystyrene Microplastic Differently Affects Redox Balance in the Anterior and Posterior Intestine of Sparus aurata.

Microplastics (MPs) are pollutants widely distributed in aquatic ecosystems. MPs are introduced mainly by ingestion acting locally or in organs far from the gastroenteric tract. MPs-induced health consequences for fish species still need to be fully understood. We aimed to investigate the effects of the subchronic oral exposure to polystyrene microplastics (PS-MPs) (1-20 µm) in the gilthead seabreams (Sparus aurata) used as the experimental model. We studied the detrimental impact of PS-MPs (25 and 250 mg/kg b.w./day) on the redox balance and antioxidant status in the intestine using histological analysis and molecular techniques. The research goal was to examine the anterior (AI) and posterior intestine (PI) tracts, characterized by morphological and functional differences. PS-MPs caused an increase of reactive oxygen species and nitrosylated proteins in both tracts, as well as augmented malondialdehyde production in the PI. PS-MPs also differently affected gene expression of antioxidant enzymes (i.e., superoxide dismutase, catalase, glutathione reductase). Moreover, an increased up-regulation of protective heat shock proteins (HSPs) (i.e., hsp70 and hsp90) was observed in PI. Our findings demonstrate that PS-MPs are responsible for oxidative/nitrosative stress and alterations of detoxifying defense system responses with differences in AI and PI of gilthead seabreams.

Enhancement of fruit byproducts through bioconversion by Hermetia illucens (Diptera: Stratiomyidae).

Bioconversion is a biological process by which organic materials are converted into products with higher biological and commercial value. During its larval stage the black soldier fly Hermetia illucens is extremely voracious and can feed on a wide variety of organic materials. To study the impact of different fruit byproducts on the insect's growth, final larval biomass, substrate reduction, bioconversion parameters, and larval nutritional composition, 10 000 black soldier fly larvae (BSFL) were reared on 7.0 kg of one of three substrates (strawberry, tangerine, or orange) or on a standard diet as a control. The results highlight that BSFL can successfully feed and grow on each of these diets, though their development time, growth rate, and final biomass were differently impacted by the substrates, with strawberry being the most suitable. The lipid and protein contents of BSFL were similar among larvae fed on different substrates; however, major differences were detected in ash, micronutrient, fiber, fatty acid, and amino acid contents. Overall, the results indicate that fruit waste management through the BSFL bioconversion process represents a commercially promising resource for regional and national agrifood companies. Our study offers new perspectives for sustainable and environmentally friendly industrial development by which fruit byproducts or waste might be disposed of or unconventionally enhanced to create secondary products of high biological and economic value, including BSFL biomass as animal feed or, in perspective, as alternative protein source for human nutrition.

Low inclusion levels of Tenebrio molitor larvae meal in laying Japanese quail (Coturnix japonica, Gould, 1837) diet improve the intestinal morphometry, enzymatic activity and caecal short chain fatty acids profile.

One hundred twenty, 12 weeks old laying Japanese quails (JQ) were equally divided into 4 groups (6 replicates of 5 birds/group). The control group (CON) fed a corn-soybean diet; TML1.4, TML2.8, and TML5.6 groups fed a diet where a Tenebrio molitor larvae meal (TML) was included at 1.4, 2.8, and 5.6%, respectively. The trial lasted 54 days. The villi height (VH) and the crypt depth (CD) linearly decreased from the control to the TML5.6 group (P < 0.01) in the duodenum, while an opposite trend was observed for the Ab+ mucous cells count (P < 0.01). The highest VH/CD ratio was found in the TML1.4 group (P < 0.01). In the jejunum a lower VH was observed in the TML1.4 compared to the CON group; the Ab+ mucous cells increased (P < 0.01) according to the increase of the TM inclusion in the diet, while the highest VH/CD ratio (P < 0.01) was recorded in the TML2.8 group. In the duodenum only the L-ANP has been affected by TML (P < 0.001), with a quadratic and linear effect. The L-ANP is affected by the dietary treatment in the jejunum (P < 0.05), where showed a quadratic effect with the highest value in TML2.8. The % of butyric acid is maximized (P < 0.05) with the TML1.4 diet and that of the isobutyrate and valeric acids increased (P < 0.01) from TML1.4 to TML5.6. The use of TML at 1.4% in laying quail diets can be considered as a way to improve the intestinal health of the birds.

Different Combinations of Butchery and Vegetable Wastes on Growth Performance, Chemical-Nutritional Characteristics and Oxidative Status of Black Soldier Fly Growing Larvae.

Hermetia illucens larvae (five days old) were farmed on broiler feed (control diet), a vegetable diet (V100), a 50% of vegetable diet + 50% of butchery wastes (V50 + B50), and a 75% of vegetable diet + 25% of butchery wastes (V75 + B25) to evaluate their suitability. Ten kilograms of substrate and 6000 larvae composed each replicate (nine per group). Larvae were weighed and measured every two days until the 25% developed into prepupae. Larval mortality and growing indexes were calculated. Substrates, larvae, and frass chemical composition were analyzed. Larvae oxidative status and stability were measured in hemolymph and body. The V100 larvae showed the lowest live weight, length, thickness, and growth rate but had low mortality rate and high substrate reduction index and protein conversion ratio. The V100 larvae had similar protein to and lower lipids than the control ones, while the V50 + B50 and V75 + B25 larvae contained higher lipids and lower protein than the others. Despite the vegetable wastes, at different levels, the reactive oxygen species content decreased in hemolymph, and the V100 diet depressed growth performance and should be avoided. The use of butchery wastes combined with vegetable ingredients can be a suitable alternative to balance the high level of lipid and the low content of protein.