Supplementation of direct-fed microbials as an alternative to antibiotic on growth performance, immune response, cecal microbial population, and ileal morphology of broiler chickens.

An experiment was conducted to investigate the supplementation of direct-fed microbials (DFM) as an alternative to antibiotics on growth performance, immune response, cecal microbial population, and ileal morphology of broiler chickens. A total of 800 one-day-old male broiler chicks (Ross × Ross) were randomly allotted to 4 dietary treatments with 4 replicate pens per treatment (50 birds/replicate pen). The 4 dietary treatments fed for 35 d were a corn-soybean meal basal diet (control); control plus 0.1% virginiamycin, as an antibiotic growth promoter (AGP); control plus 0.1% direct-fed microbials that contained Lactobacillus reuteri (DFM 1); and control plus 0.1% direct-fed microbials that contained a mixture of L. reuteri, Bacillus subtilis, and Saccharomyces cerevisiae (DFM 2). Results showed that dietary AGP and DFM supplementation significantly increased (P < 0.05) the BW gain of broilers during 0 to 21 d. The feed intake was reduced, whereas the feed conversion was improved significantly when birds were fed DFM 2 at 0 to 7 d of age. The white blood cell and monocyte levels were significantly higher in the DFM 2 group compared with the control. In addition, feeding DFM significantly (P < 0.05) increased the plasma immunoglobulin levels where a higher level was observed in DFM 2 compared with those of the other treatments. Neither DFM nor AGP treatments affected the cecal Lactobacillus and Salmonella content; however, cecal Escherichia coli content significantly decreased in broiler chickens fed DFM and AGP. The ileal villus height, and width and total thickness of muscularis externa were significantly increased when birds were fed DFM compared with AGP and control. These results indicate that the dietary supplementation of DFM increases the growth performance of birds at an early age, stimulates the immune response, decreases the number of E. coli, and improves the ileal morphology of broiler chickens. Thus, DFM that contained a mixture of several beneficial microorganisms could be a viable alternative to antibiotics in the broiler diets.

Effect of dietary zinc proteinate supplementation on growth performance, and skin and meat quality of male and female broiler chicks.

1. An experiment was conducted to evaluate the effect of dietary zinc proteinate (ZP) supplementation on growth performance and on skin and meat quality of male and female broiler chicks. 2. A total of 240 1-d-old male and 240 1-d-old female broiler chicks were randomly distributed into 24 floor pens (12 replicate pens/sex; 20 birds/pen) and were given either 0 (Control diet) or 40 mg/kg ZP (ZP 40), resulting in a 2 × 2 factorial arrangement of treatments. 3. The growth performance of male and female broiler chicks was not affected by the ZP supplementation, but the males showed significantly higher growth performance than did females. 4. ZP supplementation increased the total thickness of skin in both sexes, and males had thicker skin than females. It also increased the collagen content of skin, but not that of meat. Males had higher skin collagen contents than did females, but no sex difference was found in the meat collagen contents. 5. ZP supplementation did not affect the shear force values of skin and meat; however, males had higher shear force values of back skin than females. ZP supplementation increased the zinc contents of thigh meat and plasma in both sexes. Males had higher zinc contents in back skin than females. 6. It is concluded that dietary ZP supplementation could increase the skin quality of broiler chicks in both sexes, particularly in female broilers, without any effect on growth performance. Male broilers have better growth performance and skin quality than females.

Effect of heating system using a geothermal heat pump on the production performance and housing environment of broiler chickens.

A geothermal heat pump (GHP) is a potential heat source for the economic heating of broiler houses with optimum production performance. An investigation was conducted to evaluate the effect of a heating system using a GHP on production performance and housing environment of broiler chickens. A comparative analysis was also performed between the GHP system and a conventional heating system that used diesel for fuel. In total, 34,000 one-day-old straight run broiler chicks were assigned to 2 broiler houses with 5 replicates in each (3,400 birds/replicate pen) for 35 d. Oxygen(,) CO(2), and NH(3) concentrations in the broiler house, energy consumption and cost of heating, and production performance of broilers were evaluated. Results showed that the final BW gain significantly (P < 0.05) increased when chicks were reared in the GHP broiler house compared with that of chicks reared in the conventional broiler house (1.73 vs. 1.62 kg/bird). The heating system did not affect the mortality of chicks during the first 4 wk of the experimental period, but the mortality markedly increased in the conventional broiler house during the last wk of the experiment. Oxygen content in the broiler house during the experimental period was not affected by the heating system, but the CO(2) and NH(3) contents significantly increased (P < 0.05) in the conventional broiler house compared with those in the GHP house. Fuel consumption was significantly reduced (P < 0.05) and electricity consumption significantly increased (P < 0.05) in the GHP house compared with the consumption in the conventional house during the experiment. The total energy cost of heating the GHP house was significantly lower (P < 0.05) compared with that of the conventional house. It is concluded that a GHP system could increase the production performance of broiler chicks due to increased inside air quality of the broiler house. The GHP system had lower CO(2) and NH(3) emissions with lower energy cost than the conventional heating system for broiler chickens.

Effect of sex and dietary organic zinc on growth performance, carcass traits, tissue mineral content, and blood parameters of broiler chickens.

Zinc (Zn) is an essential mineral for animal development and function. A study was carried out to evaluate the effect of sex and dietary organic zinc (OZ) on growth performance, carcass traits, tissue mineral content, and blood parameters of broiler chickens. A total of 240 1-day-old male and 240 female broiler chicks (Cobb × Cobb) were assigned to two dietary levels of OZ (2 × 2 factorial) with six replicates per treatment (20 birds/replicate pen). The OZ supplementation levels were 0 and 25 ppm. Results showed that OZ supplementation did not affect the growth performance of male and female broilers, but the males showed significantly better (P < 0.05) growth performance than females did. Similarly, OZ supplementation did not affect the thickness of both the back and thigh skin of male and female broilers; however, males had thicker skin than females. Dietary OZ supplementation did not affect collagen contents in the skin and meat samples. Male broilers had higher skin collagen contents than females, but no sex difference was found in meat collagen contents. OZ supplementation did not affect the shear force values of skin and meat samples. Male broilers had higher shear force values of back skin than females, but not in the meat samples. Dietary OZ supplementation increased (P < 0.05) the thigh meat Zn content in both sexes. The plasma Ca content was significantly (P < 0.05) increased by dietary OZ supplementation; however, other blood parameters were not affected by dietary OZ supplementation. Males had higher plasma glucose and cholesterol content than females. It is concluded that dietary OZ supplementation at the level of 25 ppm does not affect the growth performance and skin quality of broiler chickens but increases the Zn content in thigh meat and Ca content in plasma of broiler chickens. Male broilers had better growth performance and skin quality than females.

Supplementation of graded levels of organic zinc in the diets of female broilers: effects on performance and carcase quality.

Zinc is an essential trace element. The objective of this research was to investigate the effects of various levels of organic zinc (OZ) supplementation on growth performance and carcase quality of female broiler chickens. A total of 3200 1-d-old female broiler chicks were randomly allotted to 16 floor pens with 200 birds per pen. A maize-wheat-soyabean meal basal diet (Control) was formulated and 20 mg/kg OZ (20 OZ), 40 mg/kg OZ (40 OZ), and 80 mg/kg OZ (80 OZ) were added to the basal diet to form 4 dietary treatments with 4 replicates per treatment. The OZ source was zinc proteinate which contained 15% zinc. Results showed no significant difference between the treatments in growth performance. A significant increase in thigh skin epidermis and dermis thickness was shown in the OZ supplementation groups; however, no effect was found on the thickness of back skin epidermis and dermis. Collagen contents in breast and thigh meats were not influenced by OZ supplementation but a significant increase in collagen content was found in the back and thigh skin. This increase in collagen content was significantly greater in the back and thigh skin of OZ 80 than with OZ 20. Shear force value and zinc concentration in skins and meat were not significantly influenced by supplementation with OZ. It is concluded that dietary OZ does not improve growth performance of broilers; however, it could increase skin thickness by increasing collagen content in skin, thereby improving carcase quality.