Antibiotic growth promoters have been used for growth promotion of chickens in poultry industry since 1940. Recently, concerns have been raised to the use of antibiotic growth promoters in livestock due to development of antibiotic resistance in bacteria. The objective of our study was to investigate the effect of penicillin supplementation in the feed on cecal microbiota of broiler chickens. Two groups (n = 30) of chickens were fed corn-soybean meal diets with and without supplementation of penicillin at the concentration of 55 mg/kg (ANT vs. CON, respectively). At 18 d of age, the ANT group had significantly (P ≤ 0.05) higher mean BW than the CON group (668.6 vs. 570.0 g). Cecal samples of 5 randomly selected birds were pooled from each group and used for genomic DNA isolation and PCR amplification of 16S rRNA gene; 454 pyrosequencing of the amplicons resulted in 7,881 and 11,214 sequence reads for ANT and CON groups, respectively. Phylogenetic analysis indicated that penicillin supplementation in the ANT group resulted in an elevated proportion of phylum Firmicutes from 58.15 to 91.5% and a decreased proportion of phylum Bacteroidetes from 31.1 to 2.96% compared with the CON group. Recent studies conducted in humans, pigs, and mice have shown a similar shift in gut microbiota in obese individuals compared with the lean ones, indicating that this microbial shift could be responsible for the increase in energy harvest and BW. The results of this study suggest that the growth-promoting effect of penicillin supplementation in broilers may be mediated by a similar microbial process.

1. This study was carried out to evaluate the impact of ginger (Zingiber officinale) feed supplementation on growth performance, antioxidant status, carcass characteristics and blood parameters in broiler chicks under conditions of heat stress (32 ± 2ºC for 8 h per d). 2. A total of 336 d-old male broiler chicks (Cobb-500) were randomly assigned to one of 6 dietary groups representing: basal diet with no supplement as control, basal diet containing 100 mg/kg vitamin E as positive control, basal diets containing either 7.5 or 15 g/kg of ginger root powder, and diets containing 75 or 150 mg/kg of ginger essential oil. 3. The results indicated that at 22 d of age, the group receiving 7.5 g/kg of ginger root powder experienced significantly increased body weight (BW) and body weight gain (BWG) compared to the control group. There were no significant difference among the diet groups regarding BW, BWG, feed intake (FI) or feed conversion ratio (FCR) at 42 and 49 d of age. 4. The inclusion of powder and essential oil of ginger in broiler diets did not affect carcass characteristics and blood parameters of the chickens. However, in the group receiving 150 mg/kg ginger essential oil, the total superoxide dismutase (TSOD) activity in liver increased compared to the control group. Malondialdehyde (MDA) concentrations in liver also decreased in the groups receiving ginger powder and essential oil compared to that in the control group. There were no significant difference between experimental groups regarding glutathione peroxidise (Gpx), TSOD and catalase (CAT) enzymes in red blood cells. All dietary groups increased total antioxidant capacity (TAC) and decreased MDA concentration in serum compared to the control group. 5. The results of this study suggest that ginger powder and essential oils may be a suitable replacement for synthetic antioxidants in broiler diets. Results also suggest that ginger powder might be better than extracted essential oil for improving antioxidant status in broilers.

This study was conducted to investigate the effects of the replacement of drinking water by herb infusions on the performance, relative weight of internal organs, hematocrit and immune response to Newcastle disease virus of broiler chickens. A total of 540 male broiler chicks (Ross 308) were divided into five groups, corresponding to four different treatments and one control group. Treatments were replicated eight times, and the control group four times. Experimental treatments included infusions (5 grams per liter) of cinnamon, thyme and turmeric in equal ratios in replacement of drinking water. Experimental period lasted 21 days and all chicks were fed with a corn-soybean based diet. Results showed that all herbs infusions caused significant (p<0.05) decrease in live body weight compared with the control group at 21 days of age. Mix treatment significantly decreased relative carcass weight relative to the control group (p<0.05). Herbs infusions increased the relative weight of some organs. None of herb additives affected hematocrit in comparison to control group. Cinnamon and herb mix infusion significantly improved bird immune response to the NDV vaccine in comparison to the control group and those that received only turmeric infusion. When all in-water additives were compare to each other, the birds supplemented with turmeric infusion showed the worst performance and immunity. The results of this experiment suggest that these herbs infusions did not favor the performance of broiler chickens

A total of 660 one-day-old Ross 308 broiler chicks were randomly distributed into eleven dietary treatments. Treatments included a maize-soybean meal-based diet with recommended calcium (Ca) and non-phytate phosphorus (nPP) (positive control; PC), an nPP-deficient diet (negative control; NC), NC diets supplemented with different levels of phytase (0, 500, 1,000, 2,000, 3,000, 4,000, 5,000, and 6,000 FTU/kg), a NC diet plus 0.15% myo-inositol, and a NC diet with reduced Ca level (Ca to nPP ratio same as PC). Feeding the NC diet had no effects on birds' body weight (BW), weight gain (WG), feed intake (FI), and feed conversion ratio (FCR), but decreased (P < 0.05) tibia P contents, crude protein (CP) digestibility, and serum P, but increased (P < 0.05) serum alkaline phosphatase (ALP) activity at 21 d of age. Phytase supplementation at ≥4,000 FTU/kg improved (P < 0.05) BW, WG and digestibility of nutrients. Feeding the NC diet resulted in greater (P < 0.05) litter moisture content (42 d) and poorer gait score (21 d), but 4,000 and 6,000 FTU/kg phytase returned (P < 0.05) these parameters to that of the PC. Supplemental myo-inositol increased (P < 0.05) serum total protein, P retention, and decreased (P < 0.05) litter moisture at 42 d of age. Feeding the low Ca NC diet increased (P < 0.05) serum total protein, ileum Ca, P, and CP digestibility and decreased serum ALP activity, litter moisture and gait score compared to the NC group. In conclusion, phytase in a dose-dependent manner, especially at ≥4,000 FTU/kg levels, was effective in overcoming the negative consequences of NC diets, primarily due to the ability to improve nutrient utilization. In addition, reducing the Ca level or supplementation of inositol of NC diet can correct some the negative effects of feeding a NC diet confirming the negative effect of a wide Ca: P ratio in a P-deficient diet and suggesting that inositol may play a role in the response to phytase addition.

A study was conducted to evaluate the combined effects of garlic, oyster mushroom and propolis extract on the growth performance, organ weights, antibody response to Newcastle Disease Virus (NDV), serum lipid concentrations and nutrient digestibility of male broilers. A total of 192 day old chicks (Ross 308) were randomly assigned to 3 treatments with 4 replications (16 birds per replication). Experimental treatments were a maize- soybean based diet as control, control diet supplemented with a combination of garlic (30 g/kg), oyster mushroom (2 g/kg) and propolis extract (0.2 g/kg) known as GMP, and control diet supplemented with Virginamycin (0.25 g/kg) as antibiotic. The inclusion of GMP decreased (p < 0.05) live body weight, average daily gain and feed intake but had no effect on feed conversion ratio when compared to control diet. GMP and antibiotic had no effects on relative weight of organs. Antibiotic decreased (p < 0.05) the relative weight of small intestine segments. GMP decreased total cholesterol but did not affect other serum lipids when compared to control group. Antibiotic increased (p < 0.05) cholesterol concentration in serum. The inclusion of GMP to the diet improved antibody response to NDV when compared to control and antibiotic diets. In conclusion, the results showed that GMP decreased growth performance but improved immunity of broiler chickens. More studies should be performed to confirm the action modes of such combinations