University of Khartoum

bioavailability of calcium

bioavailability of calcium

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Title: bioavailability of calcium
Author: Abd Elgadir, Omer
Abstract: Feed represents about 60-65% of production cost of poultry projects. The balanced feed is considered as a corner stone of meeting chicken nutrients requirements and minimizing feed loss. Hence all nutrient compounds needed for growth and production should be availed at exactly required level (Without excess or deficiency). Calcium is one of the most abundant elements in the body and is often the major cation in the diet. 99% of the body calcium is located in the skeleton. The remaining 1% is extremely important in cellular metabolism, blood clotting, enzyme activation and neuromuscular action. Most feed stuffs of plant origin are deficient in calcium because calcium in feed stuffs from plants quite often exists as complexes with phytate and oxalate (chelates), which reduce bioavailability. Hence a ready absorbable source of calcium should be supplemented to plant feed stuff sources. Since not all consumed calcium is available for metabolic requirement, but part of the ingested amount of calcium is absorbed and utilized and can therefore contribute to metabolic requirements. Different sources of calcium are available in Sudan which can be used to meet calcium requirement in poultry feed such as bone meal, lime stone, marble dust and oystershell. This study was conducted to determine the bioavailability of calcium from different locally available sources, by feeding day old broiler chicks with different levels of calcium sources using dicalcium phosphate as a reference standard. A basal diet was formulated to contain low calcium percentage (0.79%), referred to as 0% calcium, and was supplemented with three other levels; 0.25, 0.5 and 0.75%, resulting in dietary calcium percentage of about 1.04, 1.29 and 1.54% respectively for each calcium source. The first experiment was conducted in summer season, replicated in winter season and resulted in the following: II Significant (P<0.05) differences in total feed intake (g/bird) due to calcium sources and levels during winter season were observed while no significant difference was shown in Summer season. The same pattern of feed intake response had been shown in final body weight gain in birds fed different calcium sources; however, birds exhibited a decline pattern of body weight gain by increasing dietary calcium level for both experiments. Dry matter digestibility of the birds fed the basal diet was significantly (P<0.05) higher than that of the birds the fed the other calcium levels, while calcium source had no effect on dry matter digestibility in both experiments. There were no seasonal differences in bone ash, while significant (P<0.05) differences were observed for the birds fed different calcium levels in a positive correlation response. No seasonal, calcium source or level effects were observed in plasma calcium content, but it tended to decrease in the birds fed increasing dietary calcium levels, and those raised in winter season compared to their counterparts raised in summer season. Relative biological values of calcium from different calcium sources were not statistically different and ranged between 97.7 and 100.1%. Compared to the reference standard dicalcium phosphate (100%). The relative biological values of calcium were 100.1, 99.5, 98.3 and 97.7% for lime stone, bone meal, marble dust and oyster shell respectively. As a conclusion for this study the locally available calcium sources seemed to have similar bioavailability under the conditions of the study, and the assay method of bioavailability used.
Description: 142 Pages
URI: http://khartoumspace.uofk.edu/handle/123456789/8523
Date: 2015-04-08


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