In This study, 48 broiler chicks were used in 8 groups to evaluate the optimum time of pre-slaughter feed withdrawal (FW) for broiler chickens in order to investigate the effect of different pre-slaughter feed withdrawal periods (0.0, 4.0, 8.0 and 12.0 h) and live body weight grade at slaughter (grade A1 from 1800 to 2000g and grade A2 from 1600 to 1800g) on weight loss, carcass parts, carcass traits, giblets weight, gizzard content weight, water holding capacity (WHC) and pH values of breast and thigh meat. Some blood plasma constituents (glucose, triglycerides, uric acid and total lipids) and chemical composition of meat as well as determining its effects on meat yield. The obtained results showed that both of relative and absolute weight loss, carcass parts, dressed carcass, protein and ash content of thigh and breast meat, WHC values were significantly (p≤0.01) increased gradually with the increasing of FW period from 0.0 up to 12.0 h before slaughtering. On the other hand, both of absolute and relative weight of abdominal fat, giblets and gizzard content, concentration of glucose, pH value and moisture and fat content of breast and thigh meat decreased as the FW period increased. It were observed that the higher values of plasma triglycerides and total lipids were recorded for broiler of 8.0 h FW experimental group. Results show that the weight grade had significant (p≤0.01) effects on the absolute weight of abdominal fat, carcass parts and dressed carcass, relative weight of giblets, chemical composition of meat and W H C and pH values. In the same way the relative weight loss, abdominal fat and thigh weight and concentration of glucose was significantly (p≤0.05) affected by weight grade. However, absolute weight loss, gizzard content and giblets, as well as, relative weight of dressed carcass and concentration of uric acid, plasma total lipids and triglycerides were not significantly affected by weight grade. It was observed that the grade A2 had higher values of relative weight loss, gizzard content and giblets than grade A1 by about 7.9, 11.5 and 9.3%, respectively. In comparison the grade A1 had higher values of absolute weight of abdominal fat, carcass parts and dressed carcass than grade A2 by about 20.1, 16.5, 14.8 and 14.1%, respectively. This study revealed that the optimum feed withdrawal times pre-slaughter for broiler chickens ranging from 8.0 to 12.0 h showed the best results of carcass traits and quality. In addition, the slaughtering of broilers at 1600-1800g resulted in better values of the same traits than those slaughtered at 1800-2000g.
The study was performed to evaluate the effect of vitamin C and/or folic acid on performance, some blood constituents, oxidative stress marker (malondialdehyde (MDA), some physiological measurement (body temperature, respiration rate and blood (pH) and immune response to sheep red blood cells (SRBC's) of Al-Salam laying hens under hot environmental temperature of summer month's conditions in Egypt. A total number of one hundred and twenty, 30 th weeks old Al-Salam hens were randomly selected and distributed into four equal groups, 30 birds each, in three replicates, 10 birds each. Birds in the 1 st group were served as control, while those in the 2 nd group were fed on a diet with vitamin C (250 mg/kg diet). The 3 rd group was received a diet supplemented with folic acid (1 mg/kg diet) whereas, the 4 th group was given a diet inclusive vitamin C plus folic acid. All groups were put under observation for 16 weeks. Supplementing heat-stressed laying hens with vitamin C and folic acid improved performance compared to the control group. Digestibility of dry matter, organic matter, crude protein and ether extract were highest in the vitamin C and/or folic acid groups and lowest in the control group (P < 0.05). Retention of Ca, P, Zn and Cu were highest in the vit. C + folic acid group and lowest in the control group (P < 0.05). Furthermore, serum malondialdehyde (MDA), cholesterol and glucose concentrations decreased, whereas, serum total protein, albumin, globulin, calcium and phosphorus concentrations increased with dietary vitamin C and folic acid supplementation (P < 0.05) compared with the control group. However, the combination of vitamin C and folic aid provided greatest results. Body temperature, respiration rate and blood pH were lower in the vit. C + folic acid group and higher in the control group. The results showed that heat exposure reduced antibody titer against sheep red blood cells (SRBC's). However, vitamin C and/or folic acid supplementation enhanced humoral antibody response against SRBC's. The results of the study indicate that, separately or in combination, vitamin C and folic acid supplementation attenuates the decline in performance and antioxidant status caused by heat stress. Such supplementation may offer protection against heat stress-related depression in performance of local laying hens.
This experiment was conducted to investigate the effect of the incubator system and broiler strain on broiler performance, carcass traits and economic evaluation. Total number of 900 hatchable eggs were distributed in a factorial arrangement 2×3 with 2 incubator system [multi stage (MS) and single stage (SS)] and three broiler strains [Cobb (CB), Avian (AV) and Indian River (IR)] totaling six groups with three replicates (50 eggs of each). After complete hatching, 180 unsexed broiler chicks one day-old were wing-banded, weighed individually and divided into at the same design into 18 floor pens according to their incubator system and strain. Live body weight, weight gain, feed consumption and feed conversion ratio were measured at 7, 14, 21, 28 and 35 days of age. Carcass traits, blood plasma constituents and economic efficiency were recorded at the end of trial (day 35). The broiler chicks produced from (SS) had significantly differences in live body weight, weight gain, feed consumption and feed conversion ratio than those produced from (MS). The same trend was observed in (AV) strain for these traits than the other strains (CB) and (IR).Carcass traits and blood plasma constituents showed insignificant figures in most parameters. Blood parameters showed insignificant figures in most parameters. However AST activity and A/G ratio have significant difference (P≤0.05) for (AV) strain and their interaction with incubator system (SS) than the other groups. The incubator system (MS) had highest net return and economic efficiency compared with the incubator system (SS). While, Avian broilers strain had the highest net return, economic efficiency and performance indexes compared to Cobb and Indian River broiler chick strains. These results conclude that the incubator system (single stage) realize the best values of most productive performance traits, also Avian strain was recorded higher productive performance compared with as compared with Cobb and Indian River strains. The best economic efficiency and performance index were recorded for Avian broiler chicks strain which produced from incubator system (multi stage).
A study was conducted to investigate the effect of two dietary herbal plants (fenugreek seeds (F), marjoram leaves (M) and their combination (F+M)) supplementation on productive performance and carcass traits of New Zealand White rabbits (NZW). The herbal plants were dietary added for 8 weeks at the following levels: T1 (0% F+0% M), T2 (0.25%F), T3 (0. 25%M), T4 (0.50%F), T5 (0.50%M), T6 (0.25% F+0.25% M), T7 (0.50% F+0.25% M), T8 (0.25% F+0.50% M) and T9 (0.50% F+0.50% M). Ninety unsexed rabbits at 6 week of age (750-775g initial body weight) were divided into 9 treatment groups. Each treatment had 10 rabbits. At the end of the feeding traits, no significant differences were observed in LBW of rabbits comparing with the control group. However, group 4 which fed fenugreek (0.50%) achieved the highest final LBW at 14 weeks of age. During the whole period, means of feed consumption of rabbits were not significantly different among experimental groups. Concerning feed conversion ratio (FCR) for the whole experimental period, there were no significant differences among all groups. Herbal plants supplementation had no significant effect on relative weights of carcass yield, liver or heart. Generally, the present study concluded that the consumption of fenugreek and marjoram had positive effects on rabbit's performance and carcass traits of growing NZW rabbits.
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