The effects of organic acid, probiotic and a combination of the two on performance and gut morphology in broiler chickens were investigated. Two hundred and forty one-day-old Arbor Acre broiler chicks were randomly assigned to five dietary treatments with six replicates, each with eight birds. The treatments were basal diet (negative control, NC), basal diet + antibiotic (positive control (PC)), NC + 0.4% organic acid (OA), NC + 0.3% probiotic (PB) and NC + 0.4% OA and 0.3% PB. Reduced body weight gain (BWG) was recorded for birds on the NC diet at the starter phase and over the total period. The addition of OA significantly increased BWG compared to values obtained in birds on the NC and other diets. Diet had no effect on BWG at the grower phase or on feed intake, dry matter intake and feed conversion ratio in any growth phase. Gain : feed ratio was lowered in the NC diet, but improved significantly by OA and PB in the starter phase. Organic acid supplementation reduced the weight of the bursa of Fabricius. The weight of pancreas, height of villi and crypt depth were reduced in birds on the NC diet compared with those on OA, PB and a combination of these. Diet had no effects on the weights of the lungs, heart, spleen, kidneys, liver, villus width, villus height : crypt depth ratio, lactic acid bacteria, coliform bacteria and total bacterial count in any gut section. In conclusion, supplementation of broiler diets with OA and PB could improve their growth and gut morphology better than antibiotics would, with a greater positive effect in the starter phase. ______________________________________________________________________________________

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The effect of dietary supplementation of fish oil on performance and gut health of broiler chickens was examined. Two hundred one-day old broiler chicks were randomly allotted to 4 treatments with 5 replicates of 10 birds each in a completely randomized design. Diet 1: basal diet without feed additives. Diet 2: basal + coccidiostat (0.06%), Diet 3: basal + 2.5% fish oil and Diet 4: basal + 5% fish oil. Performance indices were measured. On day 56, distal ileum of two birds per replicate were severed for gut morphological measurements and digesta samples were collected for protozoan load counts. About 5cm of the jejunum, ileum and caeca were excised for histological examinations. The results showed that dietary fish oil supplementation did not have significant effect on the performance of broiler chickens at the starter phase. However, there was a negative effect of the fish oil in the final weight and feed conversion ratio of birds at the finisher phase. Final weights of birds that received the basal diet (1736g/b) were significantly higher (P< 0.05) than those placed on 5% fish oil supplemented diet (1556.3g/b). Crypt depth and villus height of birds fed with 5% fish oil supplemented diet were significantly higher (P<0.05) than those on the other diets. Birds on the control diet had numerous coccidia while fewer coccidia were observed in birds fed coccidiostat, 2.5% and 5% fish oil diets. Photomicrographs of the jejunum, ileum and caeca of birds fed the basal diet showed numerous developing stages of coccidia in the degenerated enterocytes, loss of villi and cryptal degeneration. Those on coccidiostat diet showed fusion, atrophy of villi and necrosis of mucous cells. However, in birds fed 2.5% and 5% fish oil supplemented diets; mild expansion of lamina propria and normal mucosa with no observable lesions were recorded. In conclusion, dietary supplementation of 2.5 or 5.0% fish oil resulted in adverse effect on broilers performance (body weight and FCR) accompanied with slight improvement of gut health.

In order to improve livestock production and curb the losses from diseases occurrence in livestock, producers resort to the use of antimicrobials as growth promoters to inhibit the growth of disease-causing organisms. Freshly harvested pawpaw leaves were extracted using three solvents: ethanol, methanol and n-hexane and their phytochemicals determined using standard procedure. The inhibitory activities of the extracts at low (200ppm) and high (1000ppm) concentrations against Aspergillus niger and Escherichia coli were also determined. Results obtained showed that alkaloid, flavonoid, saponin, tannin and cardiac glycosides were present while anthraquinone was absent. The percentage yield of phenols using methanol (0.115%) and ethanol (0.214%) solvents were similar but lower than nhexane yield (0.450%). Also the yield of flavonoid using methanol (0.700%) is significantly (p<0.05) higher than the yield using other solvents. The yield of phenols using methanol (0.480%) and ethanol (0.470%) solvents were identical but higher than n-hexane yield (0.400%). At low concentration, it was observed that the inhibitory concentrations of pawpaw leaf extract against bacteria by control, streptomycin (1.2cm) was significantly (p<0.05) higher but similar to the extract from methanol solvent (1.1cm). Methanol extract inhibition was also similar to ethanol (1.0cm) but higher than n-hexane (0.0cm). At high concentration, the inhibitory activity of the ethanol extract (1.2cm) was significantly (p<0.05) higher than the control (0.7cm) and the least observed in n hexane (0.0cm) extract. The inhibitory concentrations of pawpaw leaf extract against fungi Aspergillus niger at low (2.2cm) and high (2.2cm) concentrations, the methanol extract was observed to be significantly (p<0.05) higher than other extracts including control. The results suggest that using methanol-extracted pawpaw leaf as alternatives to synthetic antibiotic in animal production is effective against microbial organisms. Thus the occurrence of resistance to antibiotic or its residues on animal products will be reduced.

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