Browsing by Author "Vargas-Bello-Perez, E."

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    Effect of dietary Quillay polyphenols on the oxidative quality of broiler meat
    (2019) Fellenberg, M. A.; Pena, I.; Ibanez, R. A.; Vargas-Bello-Perez, E.
    This study evaluated the effect of the dietary inclusion of Quillaja polyphenols on the antioxidant status of the animal and the oxidative quality of meat. One hundred and twenty-eight broiler chickens were assigned to the following experimental groups, T0: basal diet (control), T1: 500 mg/kg of extract 1 + basal diet, T2: 1000 mg/kg of extract 1 + basal diet, T3: 2000 mg/kg of extract 1 + basal diet, T4: 500 mg/kg of extract 2 + basal diet, T5: 1000 mg/kg of extract 2 + basal diet, T6: 2000 mg/kg of extract 2 + basal diet, and T7: 100 mg/kg of a-tocopherol (Vit E) + basal diet. Quillaja extract 1 was composed by 10% of extracts soluble in water, with 90% of particles smaller than an 80-mesh sieve, without additives. Quillaja extract 2 was composed by 8% total phenols, 2% of tannins and 0.2% of saponins. The animals were slaughtered on d 42 and samples of intra-cardiac blood and tissue samples (liver, breast and thigh) were taken and assigned to treatments of 0, 2, 4 and 6 d of refrigeration. Feed conversion and FRAP (Ferric Reducing Ability of Plasma) index were not affected by treatments. Compared with extract 1 treatments, control had higher lipid oxidation in liver (basal and induced oxidation) and thigh (induced and induced with Fe). Compared to extract 2 treatments, control induced higher lipid oxidation + Fe. Overall, the Quillay polyphenol extracts had the same protective effects against lipid oxidation as compared to those from Vit E group in broiler thigh tissue. This study is important for those producers looking to ameliorate lipid oxidation problems in meat.
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    Effect of dietary vitamin E supplementation on glutathione concentration and lipid and protein oxidation of refrigerated broiler meat
    (2019) Fellenberg, M. A.; Pena, I.; Ibanez, R. A.; Vargas-Bello-Perez, E.
    This study evaluated the effect of dietary supplementation of vitamin E on glutathione content, and lipid and protein oxidative stability during refrigerated storage of broiler meat. Ninety one-d-old chicks were randomly assigned to one of two groups. The control group had a basal diet and the vitamin E (Vit E) group received 200 mg/kg alpha-tocopheryl-acetate as a supplement for 42 d. Lipid oxidation was assessed by the thiobarbituric acid reactive substances (TBARS) method, protein oxidation was estimated by carbonyl content and glutathione was measured by thiol content. Oxidised protein content in breast tissue remained stable during 6 days of refrigerated storage at 4 degrees C. In thigh tissue, the oxidised protein content significantly increased at 4 d of storage and then decreased. The TBARS content of meat of chickens supplemented with Vit E was lower than that from control during all time points of refrigerated storage. Meat from Vit E treated chickens had lower TBARS content than control meat when estimated at temperature-induced lipid oxidation conditions. In control meat, the TBARS content increased until 4 days of cold storage and then decreased at 6 days. The glutathione content of refrigerated breast tissue in all treatments remained constant during the first 4 d of refrigerated storage but exhibited a decrease thereafter. This research confirms that Vit E supplements in chicken feed protect their meat from lipid oxidation.
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    Effect of Feeding Lucerne and a Mixed Diet of Oats and Berseem Clover as a Source of Fresh Forage on Ruminal Characteristics and Nitrogen Use Efficiency in Dairy Cows during the Winter Period
    (2022) Enriquez-Hidalgo, D.; Barrera, K.; Rivero, M. J.; Merino, V. M.; Teixeira, D. L.; Vargas-Bello-Perez, E.
    The inclusion of fresh forages into dairy cows' diets during the winter can represent economic and nutritional benefits but can affect cows' metabolic function. The study aimed to evaluate the effect of using fresh berseem clover/oat (MIX), fresh lucerne (LEG) and hay/silage (CON) as forage basis for total mixed ration during the winter period on dairy cows' rumen characteristics and N metabolism. Three non-lactating rumen-cannulated cows were allocated to each diet for a 14-day period in a 3 x 3 Latin Square design. Sample collection occurred on the last 3 days of each period. Rumen fluid samples were analysed for pH, volatile fatty acids and N-ammonium contents. In situ forage nutrients degradability were evaluated by ruminal incubation. Serum, urine and faecal samples were collected and analysed for N content. Cows had similar feed intakes. No major changes were observed in rumen characteristics, but LEG led to greater ruminal N-ammonium and ammonium ureic N contents. Fresh pasture diets reduced the daily urine ureic N. The fresh forages improved the ruminal kinetics of dry matter and crude protein. The forage nutrients' effective degradability was greater for the fresh pasture diets than for CON. Overall, inclusion of fresh forages had minor effects on ruminal parameters, but the use of the MIX diet represents a suitable option in terms of N use efficiency.
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    Short communication: Chemical composition, fatty acid composition, and sensory characteristics of Chanco cheese from dairy cows supplemented with soybean and hydrogenated vegetable oils
    (2015) Vargas-Bello-Perez, E.; Fehrmann-Cartes, K.; Iniguez-Gonzalez, G.; Toro-Mujica, P.; Garnsworthy, P. C.
    Lipid supplements can be used to alter fatty acid (FA) profiles of dairy products. For Chanco cheese, however, little information is available concerning effects of lipid supplements on sensorial properties. The objective of this study was to examine effects of supplementation of dairy cow diets with soybean (SO) and hydrogenated vegetable (HVO) oils on chemical and FA composition of milk and cheese and sensory characteristics of cheese. Nine multiparous Holstein cows averaging 169 +/- 24 d in milk at the beginning of the study were used in a replicated (n = 3) 3 x 3 Latin square design that included 3 periods of 21 d. All cows received a basal diet formulated with a 56:44 forage:concentrate ratio. Dietary treatments consisted of the basal diet (control; no fat supplement), and the basal diet supplemented with SO (unrefined oil; 500 g/d per cow) and HVO (manufactured from palm oil; 500 g/d per cow). Milk fat yield was lower with HVO compared with control and SO. Cheese chemical composition and sensory profile were not affected by dietary treatment. Vaccenic (C18:1 trans-11) and oleic (C18:1 cis-9) acids were higher for SO than for control and HVO. Compared with control and HVO,. SO decreased saturated FA and increased monounsaturated FA. The thrombogenic index of milk and cheese produced when cows were fed SO was lower than when cows were fed on control and HVO. The outcome of this study showed that, compared with control and HVO, supplementing dairy cow diets with SO improves milk and cheese FA profile without detrimental effects on the chemical composition of milk and cheese and the sensory characteristics of cheese.