Agriculture and Food Systems - Research Publications

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    A Dietary Sugarcane-Derived Polyphenol Mix Reduces the Negative Effects of Cyclic Heat Exposure on Growth Performance, Blood Gas Status, and Meat Quality in Broiler Chickens
    Shakeri, M ; Cottrell, JJ ; Wilkinson, S ; Le, HH ; Suleria, HAR ; Warner, RD ; Dunshea, FR (MDPI, 2020-07-01)
    Heat stress (HS) compromises growth performance and meat quality of broiler chickens by interrupting lipid and protein metabolism, resulting in increased oxidative damages. The experiment attempted to investigate whether dietary polyphenols (Polygain (POL)) could ameliorate the aforementioned adverse effects of HS on performance and meat quality. One hundred and twenty one day-old-male chicks were allocated to two temperature conditions, thermoneutral (TN) or HS, and fed with either a control diet (CON) or the CON plus four different doses of POL (2, 4, 6 and 10 g/kg). Heat stress caused respiratory alkalosis as evidenced by increased rectal temperature (p < 0.001) and respiration rate (p < 0.001) due to increased blood pH (p < 0.001). Heat stress decreased final body weight (p = 0.061) and breast muscle water content (p = 0.013) while POL improved both (p = 0.002 and p = 0.003, respectively). Heat stress amplified muscle damages, indicated by increased thiobarbituric acid reactive substances (p < 0.001) and reduced myofibril fragmentation index (p = 0.006) whereas POL improved both (p = 0.037 and p = 0.092, respectively). Heat stress impaired meat tenderness (p < 0.001) while POL improved it (p = 0.003). In conclusion, HS impaired growth performance and meat quality whereas POL ameliorated these responses in a dose-dependent manner, and effects of POL were evident under both temperature conditions.
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    Dietary Betaine Reduces the Negative Effects of Cyclic Heat Exposure on Growth Performance, Blood Gas Status and Meat Quality in Broiler Chickens
    Shakeri, M ; Cottrell, JJ ; Wilkinson, S ; Le, HH ; Suleria, HAR ; Warner, RD ; Dunshea, FR (MDPI, 2020-05-01)
    Heat stress (HS) impairs growth performance and has a severe impact on lipid and protein metabolism, leading to serious adverse effects on meat quality. Forty-eight day-old-male Ross-308 chicks were assigned to two temperature conditions, thermoneutral or cyclical HS, and fed with either a control diet (CON) or the CON plus betaine (BET). Heat stress increased rectal temperature (p < 0.001), respiration rate (p < 0.001) and increased blood pH (p = 0.017), indicating that HS caused respiratory alkalosis. Heat stress reduced body weight during the final stage of growing period (p = 0.005), while BET improved it (p = 0.023). Heat stress tended to reduce breast muscle water content and drip loss (p = 0.089 and p = 0.082), while both were improved with BET (p = 0.008 and p = 0.001). Heat stress tended to reduce the myofibril fragmentation index (p = 0.081) whereas it increased with BET (p = 0.017). Heat stress increased thiobarbituric acid reactive substances (p = 0.017), while BET improved it (p = 0.008). Meat tenderness was not affected by HS, but was improved with BET (p < 0.001). In conclusion, BET improved growth performance over the latter stages of the growing period, and improved product quality of broiler chickens when chickens exposed to HS.
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    Betaine and Isoquinoline Alkaloids Protect against Heat Stress and Colonic Permeability in Growing Pigs
    Le, HH ; Shakeri, M ; Suleria, HAR ; Zhao, W ; McQuade, RM ; Phillips, DJ ; Vidacs, E ; Furness, JB ; Dunshea, FR ; Artuso-Ponte, V ; Cottrell, JJ (MDPI, 2020-10-01)
    Heat stress (HS) compromises productivity of pork production, in part as a result of increased oxidative stress and inflammatory responses, particularly within the gastrointestinal tract. This study aimed to investigate whether plant-derived betaine and isoquinoline alkaloids could ameliorate HS in pigs. Fifty female Large White × Landrace grower pigs, which were acclimated to control (CON), control plus betaine (BET), or control plus isoquinoline alkaloids (IQA) diets for 14 days were then exposed to heat stress or thermoneutral condition. Both BET and IQA partially ameliorated increases in respiration rate (p = 0.013) and rectal temperature (p = 0.001) associated with HS conditions. Heat stress increased salivary cortisol concentrations and reduced plasma creatinine, lactate, and thyroid hormone concentrations. Heat stress increased colon FD4 permeability, which was reduced by IQA (p = 0.030). Heat stress increased inflammation in the jejunum and ileum, as indicated by elevated interleukin-1β (p = 0.022) in the jejunum and interleukin-1β (p = 0.004) and interleukin-8 (p = 0.001) in the ileum. No differences in plasma total antioxidant capacity (TAC) were observed with HS, but betaine increased plasma TAC compared to IQA. Dietary BET increased betaine concentrations in the jejunum, ileum (p < 0.001 for both), plasma, liver, kidney (p < 0.010 for all), urine (p = 0.002) and tended to be higher in muscle (p = 0.084). Betaine concentration was not influenced by HS, but it tended to be higher in plasma and accumulated in the liver. These data suggest that betaine and isoquinoline alkaloids supplementation ameliorated consequences of heat stress in grower pigs and protected against HS induced increases in colonic permeability.
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    Growth Performance and Characterization of Meat Quality of Broiler Chickens Supplemented with Betaine and Antioxidants under Cyclic Heat Stress
    Shakeri, M ; Cottrell, JJ ; Wilkinson, S ; Le, HH ; Suleria, HAR ; Warner, RD ; Dunshea, FR (MDPI, 2019-09-01)
    Heat stress (HS) causes oxidative stress, which compromises broiler performance and meat quality. The aim of this study was to determine whether dietary antioxidants could be used as an amelioration strategy. Seventy-two day-old-male Ross-308 chicks were exposed to either thermoneutral or cyclical heat stress conditions. Diets were either control commercial diet (CON), CON plus betaine (BET), or with a combination of betaine, selenized yeast, and vitamin E (BET + AOX). Heat stress increased the rectal temperature (p < 0.001), respiration rate (p < 0.001), decreased blood pCO2 (p = 0.002), and increased blood pH (p = 0.02), which indicated the HS broilers had respiratory alkalosis. Final body weight was decreased by HS (p < 0.001), whereas it was improved with BET (p = 0.05). Heat stress reduced cooking loss (p = 0.007) and no effect on drip loss, while BET decreased the drip loss (p = 0.01). Heat stress reduced the myofibril fragmentation index (p < 0.001) and increased thiobarbituric acid reactive substances (p < 0.001), while these were improved with the combination of BET + AOX (p = 0.003). In conclusion, BET overall improved growth rates and product quality in this small university study, whereas some additional benefits were provided by AOX on product quality in both TN and HS broilers.