Savaram Venkata Rama Rao

Background: Ban on utilization of antibiotic growth promoters (AGP) in poultry diets has driven the implementation of alternative strategies to maintain gut health, optimal digestibility and performance in broiler production. Lauric acid (LA) is a medium chain fatty acids and could be used as a potential alternative to AGP in broiler diets. Hence, an experiment was conducted to evaluate the effect of dietary supplementation of LA at graded levels on nutrient retention, blood biochemical constituents and gut microflora count. Methods: Three hundred, day old commercial broiler chicks were randomly allotted to 6 dietary treatments with 10 replicates of 5 chicks in each. Corn-soybean meal based basal diet (BD) was formulated for pre-starter (1-2weeks), starter (3-4 weeks) and finisher (5-6 weeks) phases without AGP (negative control). Positive control diet was the BD having 0.035% chlortetracycline as AGP. The remaining 4 experimental diets were formulated by supplementing LA to BD at rate of 0.05% (LA-50), 0.075% (LA-75), 0.1% (LA-100) and 0.2% (LA-200), respectively. Blood was collected from 1 bird per replicate on 35thd to estimate blood biochemical constituents. To assess the nutrient retention, metabolic trial of 3 d duration was conducted on one randomly selected bird per replicate after 42 d. On same day, 1 bird from each replicate was sacrificed for enumeration of total bacteria and Escherichia coli in gut. Result: The utilization of dry matter was higher (P less than 0.05) in broilers fed on graded levels of LA than BD fed chicks and was comparable to that of AGP fed birds. Broilers supplemented with LA-200 and LA-75 diet had higher (P less than 0.01) crude protein retention than those fed BD. Significantly (P less than 0.05) higher ether extract retention was observed in LA-200 fed birds compared to those on BD, AGP, LA-50, LA-75 and LA-100. Replacement of AGP with LA (0.05 to 0.2%) in diets decreased (P less than 0.05) total bacterial and E.coli count in gut. Serum glucose, cholesterol, albumin, globulin and its ratio were not affected while serum total protein was higher (P less than 0.05) in LA-75 and LA-200 fed birds compared to BD birds. Based on the results it could be concluded that, lauric acid supplementation at 0.05% in diets improved nutrient retention and gut health and could be used as alternative to antibiotic growth promoter.

A six-week feeding trial was conducted to evaluate the efficacy of a multicomponent mycotoxin detoxifying agent (MMDA) to minimize the toxic effects of combined mycotoxins (MT) supplementation in broiler diets. A total of 1584 Vencobb day-old broiler male chicks were assigned to six dietary treatments with 12 replicates of 22 birds per floor pen. Three graded levels of MMDA (0, 1.5, and 3.0 kg/ton) and two concentrations (without and with) of MT blend (aflatoxin 100 ppb, DON 200 ppb, and T-2 1000 ppb) were supplemented to maize-soybean diet in a 3 x 2 factorial manner. On the 43^rd day, carcass variables (ready-to-cook yields, relative weights of breast meat, abdominal fat) and relative weights of liver, thymus, spleen, and bursa were evaluated. Serum samples were analyzed for biochemical indices and immune responses. Liver, kidney and thigh muscle were analysed for aflatoxin B1, B2, G1, G2 and M1, T-2, HT-2, T2 Triol, T2 Tetraol, Deoxynivalenol and Deepoxy-deoxynivalenol (DOM1). The results showed that the main effects (MT and MMDA) or their interaction did not affect performance, breast meat, abdominal fat, relative weights of immune organs, and serum protein and triglyceride concentration. The inclusion of MT significantly (P<0.05) reduced the antibody titers against the ND vaccine, increased the liver weight and activities of liver function enzymes (SGOT, SGPT), and decreased the gamma-glutamyl transferase activity and serum albumin concentrations. However, the addition of MMDA to MT contaminated diet significantly reduced the concentrations of liver function enzymes. The concentrations of mycotoxins tested in the tissue were below detectable levels. Based on the results, it was concluded that the addition of broad-spectrum MMDA (at 1.5 kg/ton) to the MT-contaminated feed reduced the negative effects of MT on immune responses and liver function in broilers exposed to combined mycotoxins.

Objective: An experiment was conducted to study the effect of supplementing DL methionine (DL Met) at graded concentrations on performance, carcass variables, immune responses and antioxidant variables in broiler chicken fed folic acid (FA) fortified (4 mg/kg) lowmethionine diet.Methods: A basal diet (BD) without supplemental DL Met, but with higher level (4 mg/kg) of FA and a control diet (CD) with the recommended concentration of methionine (Met) were prepared. The BD was supplemented with DL Met at graded concentrations (0%, 10%, 20%, 30%, 40%, and 50% supplemental DL Met of CD). Each diet was fed ad libitum to 10 replicates of 5 broiler male chicks in each from 1 to 42 d of age.Results: Body weight gain (BWG) reduced, and feed conversion ratio (FCR) increased in broilers fed low-Met BD. At 30% and 20% inclusion of DL met, the BWG and FCR, respectively were similar to those fed the CD. Similarly, supplementation of 10% DL Met to the BD significantly increased ready to cook meat yield and breast meat weight, which were similar to those of the CD fed broilers. Lipid peroxidation reduced, the activity of antioxidant enzymes (GSHPx and GSHRx) in serum increased and lymphocyte proliferation increased with increased supplemental DL Met level in the BD. The concentrations of total protein and albumin in serum increased with DL Met supplementation to the BD.Conclusion: Based on the data, it can be concluded that supplemental Met can be reduced to less than 50% in broiler chicken diets (4.40, 3.94, and 3.39 g/kg, respectively in pre-starter, starter and finisher phases) containing 4 mg/kg FA.

Three experiments were conducted using growing White Leghorn pullets (Babcock BV 300) by feeding graded concentration of metabolizable energy (ME, 2500 to 3000 kcal/kg at 100 kcal/kg increment), crude protein (CP, 125 to 195 g/kg at 10 g/kg increment) and methionine (Met, 3.1, 3.4, 3.7 and 4.1 g/kg) to determine the optimal requirement of dietary ME, CP and Met based on body weight gain (BWG), feed intake (FI) and feed conversion ratio (FCR). A total of 5420, 5888 and 2576 day-old chicks were used in energy, protein and Met experiments, respectively and each diet was offered ad libitum from day 1 to 20 weeks of age to ten, eight and seven replicates (92 birds in each), respectively. BWG during starter (1-8 weeks) and overall experiment (1-20 weeks) was significantly higher in chicks fed 2800 and 2700 kcal/kg compared to the 2500 kcal/kg ME group. Similarly, the optimum BWG was observed at 165 and 135 g protein and 3.74 and 3.4 g Met/kg, respectively in starter and grower (9-20 weeks) diets. The FCR improved during all phases with energy, during starter phase with protein and Met concentration in diet. Based on the results it is concluded that White Leghorn pullets require 2800 and 2700 kcal/kg ME during starter and overall experiment phase, 165 g and 135 g/kg protein during starter and grower phases, while Met requirements for the respective phases were 3.74 and 3.4 g/kg diet for optimum weight gain.

Content: Antibiotic growth promoters (AGP) are not recommended in broiler diets due to the possible threat of microbial resistance and residues in meat. Aim: Two experiments were conducted to study the possibility of utilising coated sodium butyrate (CSB) as an alternative to AGP (500 g/t) in broiler (1–42 days) chicken diet. Method: In Experiment 1, a positive control (PC with AGP), a negative control (NC, without AGP) and CSB diet (150 g/t), and in Experiment 2, four diets, i.e. PC, NC, and CSB at two concentrations (75 and 150 g/t) were prepared. Each diet was offered ad libitum to 10 floor pens (25 broilers) with built up litter as bedding material. Key results: Bodyweight gain (BWG) and feed intake (FI) were not affected, while feed efficiency (FE) at both Day 21 and Day 42 reduced in broilers fed the NC compared with those in the AGP-fed group (Experiment 1). Inclusion of CSB (150 g/t) improved the FE similar to the AGP group. In Experiment 2, BWG and FI were not affected, while FE improved in CSB groups compared with the AGP or NC. The colony count of E. coli and C. perfringes increased in the NC group compared with the AGP group and the count in CSB groups was similar to that in the AGP group. The ileal digestibility of nitrogen (CSB150 g) and energy (CSB75 and CSB150 g) and tibia variables (total ash and breaking strength) reduced in the NC group compared with the AGP groups and supplementation of CSB improved all these parameters similar to the AGP group. Conclusions: On the basis of the data, it is concluded that CSB (75 or 150 g/t) can be used as an alternative to the AGP (bacitracin methylene disalysilate) in broiler chicken diet. The improvement in broiler performance with CSB in diet could be attributed to the increased ileal digestibility of nitrogen and energy, bone mineralisation and reduction in pathogenic bacterial count (E. coli and C. perfringes) in the gut. Implications: Use of AGP in broiler diets can be avoided with inclusion of coated butyric acid, without affecting the broiler performance.

Antimicrobial growth promoters (AGP) are used in chicken production to suppress pathogens in the gut and improve performance, but such products tend to suppress beneficial bacteria while favoring the development and spread of antimicrobial resistance. A green alternative to AGP with the ability to suppress pathogens, but with an additional ability to spare beneficial gut bacteria and improve breeding performance is urgently required. We investigated the effect of supplementation of a blend of select essential oils (cinnamon oil, carvacrol, and thyme oil, henceforth referred to as EO; at two doses: 200 g/t and 400 g/t feed) exhibiting an ability to spare Lactobacillus while exhibiting strong E. coli inhibition ability under in vitro tests and immobilized in a sunflower oil and calcium alginate matrix, to broiler chickens and compared the effects with those of a probiotic yeast (Y), an AGP virginiamycin (V), and a negative control (C). qPCR analysis of metagenomic DNA from the gut content of experimental chickens indicated a significantly (p < 0.05) lower density of E. coli in the EO groups as compared to other groups. Amplicon sequence data of the gut microbiome indicated that all the additives had specific significant effects (DESeq2) on the gut microbiome, such as enrichment of uncultured Clostridia in the V and Y groups and uncultured Ruminococcaceae in the EO groups, as compared to the control. LEfSe analysis of the sequence data indicated a high abundance of beneficial bacteria Ruminococcaceae in the EO groups, Faecalibacterium in the Y group, and Blautia in the V group. Supplementation of the immobilized EO at the dose rate of 400 g/ton feed improved body weight gain (by 64 g/bird), feed efficiency (by 5 points), and cellular immunity (skin thickness response to phytoheamagglutinin lectin from Phaseolus vulgaris by 58%) significantly (p < 0.05), whereas neither yeast nor virginiamycin showed a significant effect on performance parameters. Expression of genes associated with gut barrier and immunity function such as CLAUDIN1, IL6, IFNG, TLR2A, and NOD1 were significantly higher in the EO groups. This study showed that the encapsulated EO mixture can improve the density of beneficial microbes in the gut significantly, with concomitant suppression of potential pathogens such as E.coli and improved performance and immunity, and hence, has a high potential to be used as an effective alternative to AGP in poultry.

1. An experiment was conducted with White Leghorn layers (Babcock BV 300) to optimise the feed withdrawal schedule for egg-laying chicken (67 to 80 weeks) reared in open side poultry house during the tropical summer season. 2. Four feeding schedules (1. ad libitum access to the layer feed, 2. feed withdrawal from 9 AM-5 PM, 3. 11 AM-5 PM, and 4. 1 PM-5 PM followed by free access to the layer feed) were examined. Each feeding schedule was offered to 12 replicates consisting of 12 layers housed in four adjacent cages (45.7 × 35.6 × 43.2 cm). 3. Fasting the layer from 1-5 pm reduced egg production compared to layers fasting from 9 or 11 am. The FI/egg or unit egg mass was highest in layers fasted from 1-5 pm. In the 9 am-5 pm fasted group, the cloacal temperature (CT) increased significantly at 11 am and gradually reduced at 3 pm. In the 1-5 pm fasted group, the CT remained higher at 3 pm and 5 pm. 4. The cell-mediated immune response in layers fasted from 9 am or 11 am was higher than those fed ad libitum or 1-5 pm fasted group. Lipid peroxidation was higher in layers 1-5 pm fasted group and significantly lower LP was found in groups that fasted from 9 am or 11 am. In general, the activities of serum antioxidant enzymes (glutathione peroxidase, glutathione reductase, superoxide dismutase) were higher in layers that fasted from 9 am or 11 am compared to those that had ad libitum feed or fasted from 1-5 pm. 5. It was concluded that the feed withdrawal should be initiated during the forenoon (9 AM/11 am-5 pm) for optimum production and to reduce oxidative stress in egg-laying chicken reared during summer in the tropical region.

Objective: An experiment was conducted to determine the effects of supplementing graded concentrations of inorganic sulphur (S) without and with folic acid (FA) in maize-soybean meal diets on performance, slaughter and anti-oxidant variables, immune responses and serum protein fractions in broiler chicken.Methods: Inorganic S was supplemented at 0.05%, 0.10%, 0.15%, and 0.20% alone or in combination with FA (4 mg/kg) in basal diet (BD) containing no supplemental methionine (Met) and FA. A control group was fed with the recommended concentration of Met. Each diet was offered to 10 pens of 5 male broiler chicks (Cobb 400) and fed ad libitum from day 1 to 42.Results: The broilers fed the BD had lower body weight gain (BWG), feed efficiency (FE), higher lipid peroxidation (LP), lower activity of glutathione peroxidase (GSHPx), lower lymphocyte proliferation ratio (LPR), and reduced concentrations of total protein, albumin, and globulin in serum. Supplementation of FA and S to the BD improved the BWG (all concentrations of S) and FE (0.20% S) similar to the control group. Similarly, the combination of S and FA significantly improved the concentrations of total protein, albumin, and globulin in serum, reduced the LP and increased the activity of GSHPx and LPR. However, responses in the above parameters were related to the concentration of S in the diet. The slaughter variables and antibody titres against the Newcastle disease were not affected with the treatments.Conclusion: Based on the results, it is concluded that the combination of S (0.2%) and FA (4 mg/kg) improved the BWG and FE, similarly supplementation of these nutrients improved the concentration of protein fractions and reduced the stress (reduced LP and improved GSHPx) variables in serum and improved the cell mediated immune response (LPR) in broilers fed sub-optimal concentrations of Met in diet.