Different dietary combinations of high/low starch and fat with or without bile acid supplementation on growth, liver histopathology, gene expression and fatty acid composition of largemouth bass, Micropterus salmoides.

High dietary levels of fat and/or starch can lower the growth and cause extensive liver inflammation that is linked to mortalities in largemouth bass, Micropterus salmoides. However, bile acids (BA) may mitigate these adverse effects. In a 2 × 2 × 2 factorial feeding trial, M. salmoides juveniles were fed different combinations of dietary high (HF), low fat (LF), high (HS) or low starch (LS) levels with or without BA supplementations at 1% for 8 weeks. A total of 8 isonitrogenous diets were formulated to include, HF/LS, HF/HS, LF/HS, LF/LS, HF/LS-BA, HF/HS-BA, LF/HS-BA and LF/LS-BA. Survival, growth performance, feeding efficiency, whole-body proximate composition, muscle/liver fatty acid composition, hepatic expression of growth regulator (GH/IGF1 axis), lipid metabolism (fatty acid synthase 'FASN' and cholesterol 7 alpha-hydroxylase 'CYP7A1') and antioxidant capacity (superoxide dismutase 'SOD') genes as well as liver histopathology were assessed. Results showed that among diets without BA, there was no significant effect on growth or feeding efficiency, but when BA was included this led to more variable effects including significantly higher weight gain in the LF/HS-BA group compared to all others fed BA. The HF, HS or their combination led to extensive hepatic inflammation, but BA appeared to partially mitigate this in the LF/HS group (i.e. LF/HS-BA). No abnormal liver histopathology was observed in the LF/LS and LF/LS-BA treatments. Muscle 22:6n-3 was significantly higher in the HF/LS and HF/HS-BA groups compared to those fed the HF/HS or LF/LS diets. Dietary fat had a significant effect on the moisture, crude lipid, and caloric content of M. salmoides. Hepatic expression of IGF-I and CYP7A1 were differentially modulated under different treatments. Overall, these results show that BA can alleviate some liver inflammation caused by high dietary starch; however the LF/LS diets led to a better balance between growth performance and liver health.

Effects of bioprocessed soybean meal and nucleotide supplementation on growth, physiology and histomorphology in largemouth bass, Micropterus salmoides, juveniles.

In this 8-week feeding trial, the effects of nucleotide (N) supplementation (at 0.05%) were compared in diets with conventional soybean meal (CSBM or CSBM + N) versus bioprocessed SBM (BSBM or BSMB + N) on largemouth bass, Micropterus salmoides, juveniles. A total of five isonitrogenous and isolipidic diets were formulated, with the control diet being fishmeal-based. Growth, feeding efficiency, proximate composition, hepatic expression of genes involved in lipid metabolism and growth as well as liver/intestinal histopathology were assessed. Results showed that growth was significantly higher in fish fed the control diet, but there was no significant effect of SBM type or nucleotide supplementation on growth, feeding efficiency, or proximate composition. Hepatic expression of growth hormone (GH), insulin-like growth factor I (IGFI), superoxide dismutase (SOD), fatty acid synthase (FASN) and cholesterol 7 alpha-hydroxylase (CYP7A1) were unaffected by the diets. Tumor necrosis factor alpha (TNF-α) and transforming growth factor beta (TGF-ß) were significantly downregulated and upregulated, respectively, in the SBM-based treatments compared with the control. The intestinal villi were significantly shorter and wider in fish fed the CSBM diet compared to the other treatments. The villi height and width were similar between the control and those fed the BSMB + N diet. It may be possible that the unaffected growth by nucleotides were due to an insufficient dose and/or undisrupted nucleotide synthesis due to being cultured under good conditions. Meanwhile, the unaffected growth in the SBM treatment could indicate a tolerance of M. salmoides to plant proteins and associated antinutritional factors. Nevertheless, BSBM and/or nucleotides appeared to mitigate some adverse effects of dietary SBM to the intestinal histomorphology in M. salmoides.

Conversion of Spent Coffee and Donuts by Black Soldier Fly (Hermetia illucens) Larvae into Potential Resources for Animal and Plant Farming.

Nutritionally unbalanced organic waste can be converted into potential resources for animal and plant farming by culturing black soldier fly (Hermetia illucens) larvae (BSFL) and prepupae (BSFP). BSFL and BSFP are rich sources of protein and lipids, while the leftover excrement called "frass" can be used as an organic fertilizer. Using readily available resources, BSFL were cultured on spent coffee, donut dough or an equal blend for 35 days. Survival, productivity, daily pupation and biochemical composition of BSFL and BSFP were measured along with the nitrogen-phosphorus-potassium values of the frass. Survival was highest in the blend compared (81%) to spent coffee (45%) or dough (24%); however, BSFL and BSFP were significantly longer and heavier from dough. Stage and food significantly influenced the protein, lipid and glycogen content of the BSFL and BSFP, which tended to be higher in the latter. While fatty acids were often significantly higher in BSFL fed spent coffee, the amino acid composition of BSFL was generally higher in dough. Frass from the blend had significantly highest nitrogen content, while potassium and phosphorus were significantly higher and lower from spent coffee, respectively. Although coffee and donut dough were suboptimal substrates for BSFL, a blend of these produced BSFL and frass that were nutritionally comparable to soybean meal and many organic fertilizers, respectively.

Differential modulation of oxidative stress, antioxidant defense, histomorphology, ion-regulation and growth marker gene expression in goldfish (Carassius auratus) following exposure to different dose of virgin microplastics.

Goldfish (Carassius auratus) juveniles were exposed to virgin polyvinyl chloride microplastics (PVC-MPs) in triplicate at 0, 0.1 or 0.5 mg/L for four days. Afterwards, the histopathology of the gills, liver and intestines were examined, along with various antioxidant enzymes and indicators of oxidative damage (malondialdehyde (MDA) and hydrogen peroxide (H2O2)), in the brain, liver and gills. In addition, we also studied the expression of hepatic insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein 1 (IGFBP-1) and growth hormone (GH) receptor, while cortisol receptor (CR) and cytochrome P450 1A (CYP1A) gene expression were assayed in both the liver and gills. Histological analysis revealed PVC-MPs in the intestines at 0.1 and 0.5 mg/L, along with substantially shorter villi. The gills appeared undamaged by PVC-MPs exposure and had limited or no effect to antioxidant activity, Na+/K+-ATPase and H+-ATPase activity or plasma ion levels, but there was a prominent upsurge of the detoxification enzymes glutatione S-transferase (GST) activity and CYP1A expression. Livers showed inflammation and some occurrences of hemorrhaging and necrosis at 0.5 mg/L. While the brain showed some evidence of oxidative damage, the liver was the most susceptible to oxidative damage, based on increased MDA, H2O2 and various antioxidant enzymes. Hepatic expression of IGFBP-1 and GH receptor were significantly downregulated at 0.5 mg/L while CR was upregulated. Results indicate that exposure to environmentally relevant PVC-MP can cause oxidative damage in the brain and liver, adverse histomorphological changes to the intestine and liver and alter the gene expression in goldfish.