Plant extracts (PE) are gaining increased attention as potential alternatives to in-feed antimicrobials (AM) due to their known antimicrobial activities. This study was conducted to examine the potential of PE, a microencapsulated product composed of eugenol and garlic tincture as an alternative to AM-agent on performance and intestinal health in broilers under necrotic enteritis (NE) challenge. A total of 960 day-old mixed-sex Cobb 500 chicks were randomly distributed to 48-floor pens with 6 treatments replicated 8 times with 20 birds each. The 6 treatments were as follows: UC, unchallenged control; CC, challenged control; PE, challenged group plus PE; AM, challenged group plus AM; FAP, challenged group plus a full dose of AM with PE; HAP, challenged group plus a half dose of AM with PE in starter, grower and finisher phases. Birds in the challenged groups were inoculated with Eimeria spp. on d 9 and Clostridium perfringens on d 14. The body weight gain (BWG), feed intake (FI), feed conversion ratio (FCR), and livability of birds were compromised, and intestinal lesions and mortality were increased (P < 0.05) by NE challenge, illustrating a successful clinical NE challenge. Birds fed AM had higher BWG and FI, and lower FCR, mortality, and intestinal lesions compared to the CC group (P < 0.05). Birds fed PE had improved FCR (P < 0.05) and livability (5.8%) in an overall period compared to the CC group. On d 16, PE supplementation reduced ileal lesion scores in only male birds (P < 0.05). Birds fed PE had decreased Eimeria maxima and Eimeria acervulina oocyst counts in caecal content (P < 0.05). Birds fed PE had decreased Escherichia brunetti and total oocyst counts in caecal content, and E. acervulina oocyst counts in ileal content in only female birds (P < 0.05). On d 35, PE supplementation reduced variation of BW in both male and female birds and increased yellowness (b∗ value, 14.4%) in the thigh. These findings suggest the potential of PE supplementation in diets to improve the performance and intestinal health of birds under clinical NE as indicated by improved FCR, livability, uniformity, reduced ileal lesions, oocyst counts and increased skin yellowness. However, the protective effect of PE may not be apparent in the presence of AM in the feed.

Background/Objectives: Dietary glucose is transported across the intestinal absorptive cell into the systemic circulation by the apically located Na⁺-dependent glucose transporter 1 (SGLT1, SLC5A1) and basally residing Na⁺-independent glucose transporter 2 (GLUT2, SLC2A2). Whilst recent experimental evidence has shown that sensing of sweet compounds by the gut-expressed sweet taste receptor T1R2–T1R3 and glucagon-like peptide-2 receptor signalling are components of the pathway controlling SGLT1 expression, little is known about the mechanisms involved in the regulation of GLUT2. In this study, we tested the hypothesis that T1R2–T1R3 and its downstream signalling pathway participate in the regulation of intestinal GLUT2. Methods: We used in vivo and in vitro approaches employing a weaning pig model, a heterologous expression assay, and knockout mice for elucidating the regulation of GLUT2 by luminal sugars. Results: A plant-based sweetener formulation included in piglets’ diet led to a marked increase in GLUT2 expression in piglets’ intestine, compared to controls. The sweeteners that do not activate pig T1R2–T1R3 failed to upregulate GLUT2. There was a significant increase in GLUT2 expression when the sweetener sucralose, which activates T1R2–T1R3, was included in the drinking water of wild-type mice. However, in knockout mice, in which the genes for the sweet receptor subunit T1R3 and the associated G-protein gustducin were deleted, there was no upregulation of GLUT2 expression in response to sucralose supplementation. There was a notable increase in GLUT2 expression in wild-type mice fed a high-carbohydrate diet compared to when maintained on a low-carbohydrate diet. However, in GLP-2 receptor knockout mice kept on the high-carbohydrate diet, there was no enhancement in GLUT2 expression. Conclusions: The experimental evidence suggests that luminal sweet sensing via T1R2–T1R3 and the enteroendocrine-derived GLP-2 are constituents of the regulatory pathway controlling GLUT2 expression.

Two experiments were conducted to evaluate the relative bioavailability (RBV) and performance effects of four zinc sources: zinc sulfate (ZnSO₄), zinc glycinate (ZnGly), zinc amino acid hydrate (ZnAAH), and zinc methionine hydroxy analog (ZnMHA) in male broilers. Experiment 1 used a depletion-repletion model with semi-purified diets to assess graded supplementation levels of ZnSO₄, ZnGly, and ZnAAH (0, 5, 10, 15, or 20 mg/kg). Experiment 2 evaluated all four sources at 10 and 60 mg/kg, along with a negative control (NC, 0 mg/kg), under practical corn-soybean meal feeding conditions. In Experiment 1, supplemental zinc significantly affected BWG, FI, FCR, and tibia zinc concentration. Growth responses (BWG and FI) exhibited both linear and quadratic trends, plateauing at approximately 11.7 mg/kg zinc intake, while tibia zinc increased linearly across all levels. Organic sources (ZnGly and ZnAAH) increased tibia zinc by 11-12% and improved FCR by 1.1-1.5 points compared with ZnSO₄. RBV estimates based on tibia zinc indicated that ZnGly and ZnAAH were 42-48% more bioavailable than ZnSO₄ (P < 0.05), with no significant differences between the two organic sources. In Experiment 2, zinc source influenced BWG, FI, and FCR (P < 0.05) and tended to affect overall FCR (P = 0.07). Supplementation with ZnSO₄ and ZnGly increased overall BWG by 118 g and 104 g, respectively, compared with NC, and resulted in greater performance than ZnMHA. ZnGly reduced overall FCR by 3.6 points, while ZnGly and ZnSO₄ improved adjusted FCR by 6.8 and 5.8 points, respectively, relative to NC (P < 0.05). ZnGly increased hot carcass yield by 0.62% (P < 0.05), whereas ZnSO₄ and ZnMHA showed trends toward improvement (P < 0.10). Excreta zinc increased with supplementation across all sources, while tibia zinc increased for all treatments except ZnMHA compared with NC. Overall, organic zinc sources demonstrated greater RBV than ZnSO₄ under semi-purified conditions, primarily based on tibia zinc responses. However, under practical feeding conditions, ZnSO₄ and ZnGly produced comparable improvements in growth performance, suggesting that RBV estimates may not fully predict performance outcomes in commercial-type diets. Future research should focus on optimizing zinc strategies to enhance carcass yield and explore broader physiological roles, including footpad health, immunity, welfare, and environmental sustainability in commercial broiler production.