Effect of increasing levels of apparent metabolizable energy on laying hens in barn system.

OBJECTIVE: This experiment was to investigate the effect of increasing levels of apparent metabolizable energy (AMEn) on the laying performance, egg quality, blood parameters, blood biochemistry, intestinal morphology, and apparent total tract digestibility (ATTD) of energy and nutrients in diets fed to laying hens. METHODS: A total of three-hundred twenty 33-week-old Hy-Line Brown laying hens (Gallus domesticus) were evenly assigned to four experimental diets of 2,750, 2,850, 2,950, and 3,050 kcal AMEn/kg in pens with floors covered with deep litter of rice hulls. There were four replicates of each treatment, each consisting of 20 birds in a pen. RESULTS: AMEn intake was increased (linear, p<0.05) with inclusion level of AMEn in diets increased. Feed intake and feed conversion ratio were improved (linear, p<0.01), but hen-day egg production tended to be increased with an increasing level of AMEn in diets. During the experiment, leukocyte concentration and blood biochemistry (total cholesterol, triglyceride, glucose, total protein, calcium, asparate aminotransferase, and alanine transferase were not influenced by increasing level of AMEn in diets. Gross energy and ether extract were increased (linear, p<0.01) as the inclusion level of AMEn in diets increased. CONCLUSION: Laying hens fed high AMEn diet (i.e., 3,050 kcal/kg in the current experiment) tended to overconsume energy with a positive effect on feed intake, feed conversion ratio, nutrient digestibility, and intestinal morphology but not on egg production and egg mass.

Quality Characteristics and Composition of the Longissimus Muscle from Entire and Castrate Elk in Korea.

The objective of the research was to determine the chemical composition as well as the physicochemical properties of the longissimus muscle from Korean entire and castrate elk. Twelve elk stags were raised and fed on concentrate with ad libitum hay. All animals were equally divided into castrated and non-castrated (entire) males, and slaughtered at 5 year of age. It was found that entire elk, in comparison with castrate elk, had higher content of moisture and lower content of fat (p<0.05). Compared with entire males, the castrates had lower pH and shear force values (p<0.05). However, castrates had higher L*, a*, and b* values compared with entires (p<0.05). An analysis of the fatty acid profile revealed that the muscles of entire and castrate elk had the most abundant concentrations of the following fatty acids: palmitic acid (C16:0) of the saturated fatty acid, and oleic acid (C18:1n-9) of the unsaturated fatty acid. The entire elk contains higher proportions of linoleic acid (C18:3n6), eicosenoic acid (C20:1n9), and arachidonic acid (C20:4n6) (p<0.05). Cholesterol content in elk was not affected by castration. The predominant free amino acid was glutamic acid related to umami taste. It is apparent that the castrate animals carried higher content of histidine, isoleucine, and leucine than those of the entire group (p<0.05). In this study, it was concluded that venison quality of elk is affected by castration and these results can provide fundamental information for venison production.

The effect of castration time on growth and carcass production of elk bulls.

The effects of castration time on growth and carcass traits of elk bulls were investigated. Twelve bulls at 5 years old were raised and fed on concentrate with ad libitum hay. All animals were allocated randomly to each of four treatment groups (3 heads/group). Groups of each treatment were castrated surgically in March, April or June and managed together with non-castration (entire) treatment. All elk bulls in the trial were slaughtered at same time. Growth parameters, carcass yield and composition were recorded. The total gain and average daily gain was higher when castrated in April (p < 0.05). The entire elk produced heaviest and highest in saddle and brisket portions (p < 0.05). It is apparent that the castrate animals carried more total fat weight and percentages than the entire males (p < 0.05). It was found that loin muscles from non-castrated elk, in comparison with those from castrated one, had higher content of moisture and lower content of fat (p < 0.05). In this study, growth parameters, carcass yields and chemical composition were greatly affected by castration time.

Effects of Different Levels of Concentrate in the Diet on Physicochemical Traits of Korean Native Black Goat Meats.

The effects of feeding of diets based on roughage supplemented with concentrate on the carcass and meat quality attributes of Korean black goats were investigated. The 40 male goats at 5 mon age were divided into four treatment groups; T1 (1.5%), T2 (2.0%), T3 (2.5%) and T4 (ad libitum) feeding of concentrate with ad libitum rice straw. Forty bucks at the end of the feeding were fasted for 12 h before slaughter and were then slaughtered. For carcass measurement, cold buck carcasses were examined after 24 h of chilling at 5℃. The carcasses were chilled in refrigerator at 2±2℃ for 24 h, then the longissimus dorsi muscle was removed from the carcasses. The samples were separately vacuum packaged, frozen and stored at -20℃ for up to 1 mon, prior to physicochemical evaluations. Carcass yields were greatly affected by rate of concentrate feeding. T4 showed the heaviest live and carcass weights and the highest dressing and fat percentages (p<0.05). The moisture contents were lower in T4 compared with other treatments, while the crude protein and fat contents were higher (p<0.05). monounsaturated fatty acid in T4 was significantly higher than others, which showed the highest percentages of oleic acid (C18:1). For the sensory test, T4 was tenderer and produced better flavor scores than others. Increasing the level of concentrate in the diet resulted in an improvement in growth performance, and carcass and physicochemical characteristics of goat meats.