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Inorganic trace minerals may exacerbate lipid peroxidation, thereby impacting lipid metabolism. This study aimed to compare the effects of inorganic and coated trace minerals in diets with different fat sources, on the performance, slaughter characteristics, and antioxidant status of broiler chickens. A total of 576 21-day-old Abor Acres broiler birds were randomly divided into four dietary treatment groups in a 2 (non-coated and coated trace minerals)×2 (soybean oil and lard) factorial design. Each treatment was replicated 12 times (12 birds per replicate). The results showed that coated minerals significantly improved the average daily gain (ADG) in weight and the feed conversion ratio (P

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The objective of this study was to evaluate the effect of embryonic thermal manipulation and dietary fat source during the finisher period on carcass characteristics and breast muscle myopathies following acute heat stress. Thermal manipulation (TM) of incubation temperatures has been shown to improve bird resistance to heat stress and enhance breast muscle growth. Fat supplementation is frequently used during heat stress and fat source may alter carcass composition, as fat sources rich in unsaturated fatty acids have been shown to reduce fat pad weight. Ross 708 eggs were incubated at 37.5°C except during TM when temperature was increased to 39.5°C for 12 h daily from embryo day 7 to 16. A total of 1,080 chicks were reared under standard conditions until acute heat stress at 43 d. Dietary treatments were applied during the finisher period beginning at 28 d, with diets including 4.5% of soya oil, poultry fat, or olive oil. At 49 d, 240 male birds were processed to assess carcass and portion weights, as well as breast quality. Carcass and portion weights were decreased by TM, however percent yield was similar to the controls. A decrease in breast muscle myopathies was noted but may have been due to the lower BW of the TM birds. Interactions between the treatments suggest that TM may alter lipid metabolism. Differences in dietary fat source did not affect carcass characteristics. The reduction in breast muscle myopathies may be negated by the negative impact of TM on carcass weights. [ABSTRACT FROM AUTHOR]

SUMMARY: The objective of this study was to evaluate the effect of embryonic thermal manipulation and dietary fat source during the finisher period on carcass characteristics and breast muscle myopathies following acute heat stress. Thermal manipulation (TM) of incubation temperatures has been shown to improve bird resistance to heat stress and enhance breast muscle growth. Fat supplementation is frequently used during heat stress and fat source may alter carcass composition, as fat sources rich in unsaturated fatty acids have been shown to reduce fat pad weight. Ross 708 eggs were incubated at 37.5°C except during TM when temperature was increased to 39.5°C for 12 h daily from embryo day 7 to 16. A total of 1,080 chicks were reared under standard conditions until acute heat stress at 43 d. Dietary treatments were applied during the finisher period beginning at 28 d, with diets including 4.5% of soya oil, poultry fat, or olive oil. At 49 d, 240 male birds were processed to assess carcass and portion weights, as well as breast quality. Carcass and portion weights were decreased by TM, however percent yield was similar to the controls. A decrease in breast muscle myopathies was noted but may have been due to the lower BW of the TM birds. Interactions between the treatments suggest that TM may alter lipid metabolism. Differences in dietary fat source did not affect carcass characteristics. The reduction in breast muscle myopathies may be negated by the negative impact of TM on carcass weights.

The objective of this study was to examine the effects of supplemental feeding of full-fat extruded cottonseed pellets (FFECS) compared with tallow on carcass characteristics, sensory traits, retail display color, and fatty acid profiles, especially CLA isomers in finishing heifers. Twenty-one Angus heifers (450 ± 5 kg) were assigned randomly to 1 of 3 experimental diets: 1) 100% supplemental fat from tallow at 4.1% of ration DM (TAL), 2) a 50:50 ratio of supplemental fat from a combination of tallow at 2.1% and FFECS at 12.8% of ration DM (TAL/ECS), and 3) 100% supplemental fat from FFECS at 25.6% ration DM (ECS). All rations were formulated to contain 7.5% fat on a DM basis. Heifers were individually fed, ad libitum, for 82 d, and BW, G:F, DMI, ADG, and body composition via ultrasound were collected at 3 to 4 wk intervals. After 82 d on feed heifers were slaughtered under federal inspection, and carcass characteristics were measured (at 24 h). The LM was removed for retail display color (1, 3, 6, 10 d), Warner-Bratzler shear force (1, 3, 7, 14, 21 d postmortem aging), sensory analysis (1, 7, 14, 21 d postmortem aging), and fatty acid profile analysis. Subcutaneous fat, including all layers, was removed from the LM for fatty acid profile analysis, and ground beef patties (80:20) were produced with lean from the brisket and fat from the plate for retail color analysis (1, 2,4, 7 d). Supplemental fat source did not influence feedlot performance for any of the traits measured (P > 0.12) or any carcass traits related to yield, quality, or LM color at the 12th- to 13th-rib interface (P > 0.15). Supplemental fat source did not affect Warner-Bratzler shear force or any sensory traits (P > 0.20), but LM steaks became more tender as postmortem aging time increased up to 14 d (P < 0.01). During retail display of LM steaks and beef patties, the only difference was LM steaks from ECS were darker (lower L* value) than TAL or TAL/ECS steaks (P < 0.02). As display time increased, LM steak and beef patty objective and subjective color deteriorated (P < 0.01). Although feeding FFECS compared with tallow increased linoleic acid (C18:2n-6) in both intramuscular and subcutaneous fat (P < 0.04), this did not lead to an increase in total CLA content (P > 0.90). Full-fat extruded cottonseed pellets are interchangeable with tallow in heifer finishing diets without impacting feeding performance, meat quality, shelf life color, or CLA content of adipose sites. [ABSTRACT FROM AUTHOR]