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Various types of dietary fats undergo distinct fermentation processes by gut microbes, potentially leading to the production of neurotransmitters that can influence the gut. Serotonin and dopamine are recognized neurotransmitters with positive effects on gut function. A broiler chicken trial was conducted to evaluate the influence of dietary fat types on protein expression of 2 neurotransmitter transporters, dopamine (DAT) and serotonin (5-HTT). A total of 560 day-old (Ross 708) male broiler chicks were randomly assigned to 7 dietary treatments. The experimental treatments included a basal diet of corn-soybean meal (SBM), supplemented with 3% of various fats: poultry fat (CON), olive oil (OLIV), fish oil (FISH), canola oil (CANO), lard (LARD), coconut oil (COCO), or flaxseed oil (FLAX). Bodyweight (BW) and feed conversion ratio (FCR) were recorded. Ileal tissues were aseptically collected to determine the expression levels of DAT and 5-HTT through western blot analysis. In addition, plasma samples were analyzed for reactive oxygen metabolites (d-ROM) tests on d 55. Results showed that dietary fat type inclusion did not have any detrimental effect on growth performance parameters. The expression levels of DAT were higher (P < 0.05) in FLAX treatments compared to CON treatments on d 20 and d 55, respectively. Similarly, with 5-HTT levels, FLAX, CANO, and LARD treatments were higher (P < 0.05) than CON treatments on d 20 and d 55. However, higher levels of oxidative stress (d-ROM values) were recorded in COCO (32.75 Carr U), CANO (29 Carr U), and CON treatments (25.5 Carr U) compared to FLAX (18.5 Carr U; P < 0.05) treatment. These findings suggest that incorporating dietary flaxseed oil at a 3% level in the diet has significant potential to elevate the expression levels of intestinal DAT and 5-HTT without inducing oxidative stress., Competing Interests: DISCLOSURES The authors declare no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Understanding growth regulatory pathways is important in aquaculture, fisheries, and vertebrate physiology generally. Machine learning pattern recognition and sensitivity analysis were employed to examine metabolomic small molecule profiles and transcriptomic gene expression data generated from liver and white skeletal muscle of hybrid striped bass (white bass Morone chrysops x striped bass M. saxatilis) representative of the top and bottom 10 % by body size of a production cohort., Results: Larger fish (good-growth) had significantly greater weight, total length, hepatosomatic index, and specific growth rate compared to smaller fish (poor-growth) and also had significantly more muscle fibers of smaller diameter (≤ 20 µm diameter), indicating active hyperplasia. Differences in metabolomic pathways included enhanced energetics (glycolysis, citric acid cycle) and amino acid metabolism in good-growth fish, and enhanced stress, muscle inflammation (cortisol, eicosanoids) and dysfunctional liver cholesterol metabolism in poor-growth fish. The majority of gene transcripts identified as differentially expressed between groups were down-regulated in good-growth fish. Several molecules associated with important growth-regulatory pathways were up-regulated in muscle of fish that grew poorly: growth factors including agt and agtr2 (angiotensins), nicotinic acid (which stimulates growth hormone production), gadd45b, rgl1, zfp36, cebpb, and hmgb1; insulin-like growth factor signaling (igfbp1 and igf1); cytokine signaling (socs3, cxcr4); cell signaling (rgs13, rundc3a), and differentiation (rhou, mmp17, cd22, msi1); mitochondrial uncoupling proteins (ucp3, ucp2); and regulators of lipid metabolism (apoa1, ldlr). Growth factors pttg1, egfr, myc, notch1, and sirt1 were notably up-regulated in muscle of good-growing fish., Conclusion: A combinatorial pathway analysis using metabolomic and transcriptomic data collectively suggested promotion of cell signaling, proliferation, and differentiation in muscle of good-growth fish, whereas muscle inflammation and apoptosis was observed in poor-growth fish, along with elevated cortisol (an anti-inflammatory hormone), perhaps related to muscle wasting, hypertrophy, and inferior growth. These findings provide important biomarkers and mechanisms by which growth is regulated in fishes and other vertebrates as well., (© 2024. The Author(s).)