A total of 270 broiler chickens were used for the study. The birds were fed common diet containing 23% Crude protein and 2864 kcal kg(-1) Metabolizable energy at the starter phase while 20% Crude protein and 2923 kcal kg(-1) Metabolizable energy was fed at the finisher phase. Starter and finisher diets contained 10 and 15% inclusion levels of rice offal respectively. Granite grit was added to the basal diet at 0.0, 2.0, 4.0, 6.0, 8.0 and 10.0 g per bird per month thus making a total of six treatments. Each treatment was replicated three times with 15 birds per replicate in a completely randomized design. Packed cell volume and haemoglobin level were not significantly (p>0.05) affected by dietary grit levels while total protein increased across the graded levels of granite grit. Crude protein, crude fibre and nitrogen free extract significantly (p<0.05) improved with increasing grit levels. These parameters improved up to the highest level of grit addition (10.0 g) granite-grit. It was concluded that 10.0 g granite grit per bird per month is beneficial to broiler chickens as it allows for efficient nutrient utilization. Further study to determine the optimum level of granite grit in broiler diet is encouraged since result obtained showed the optimum level was not attained.

Mineral chelators such as organic acids have been reported to compete favourably with phytate by forming soluble complexes with feed minerals. Effect of feed grade acidifiers on total tract mineral retention and intestinal pH of broiler finisher chickens was investigated. A total of 300-broiler finisher chickens were assigned to four treatment groups. Each treatment was replicated thrice with twenty chickens per replicate in a completely randomized design. The control treatment (T1 ) was fed the control diet adequate in available phosphorus at 0.5% while other treatments (T2 -T4 ) were fed sub-optimal available phosphorus diets at 0.4%. Three blends of acidifiers; Fysal®, Orgacid® and Acidomix® were supplemented in the diets of chickens in treatments 2, 3 and 4 at 0.1% (1kg per ton/feed). Chickens fed diet supplemented  with Fysal® showed the best (P<0.05) results in total tract mineral retention 56.5+/-5.75 compared to the control and other treatments. The poor mineral retention i.e. 35 and 46% for calcium and phosphorus respectively by chickens fed the control diet was attributed to the insoluble phytate-mineral complex that limits mineral bioavailability. Intestinal segments of chickens fed acidified diets showed significant reduction (P<0.05) in pH in the range of 5.26-7.16 across duodenum to ileum compared to the control group 6.83-8.76. It is concluded that feed acidification at 0.1% improves mineral utilization in broiler chickens as it competes favourably with phytate in the lumen of the gut leading to better nutrient utilization.

The performance of broiler finisher chickens fed varied levels of mango seed kernel meal as replacement for maize was studied. Mango seed kernel was fed as replacement for maize at 0, 20, 40, 60, 80 and 100% for treatments 1-6, respectively. 20% mango seed kernel showed the best result in feed intake, average daily weight gain, feed to gain ratio and feed cost per kilogram weight gain. This performance declined with increasing replacement levels of MSK. Thus, in the study, it is concluded that) mango seed kernel can replace maize at 20% in the diet of broiler chickens without negatively affecting performance. Higher inclusion levels beyond 20% resulted in declined feed intake and productive parameters.

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