Effect of Sprouting on Chemical Composition and Performances of Improved Chickens Fed with Hydroponic Sorghum Fodder (HSF)

Dissertation

Raising chickens is rapidly gaining popularity in the developing world. However, high feed costs associated with intensive poultry rearing as well as increased competition between humans and animals/chicken on feed demand have necessitated the need for exploring new options in chicken feeding. Furthermore, chickens have a limited foraging range a factor that translates in a very narrow array of feeds they can access. Sorghum is one such feedstuff which is widely grown in Tanzania and has nutritional value almost similar to maize and also drought-resistant crop. Given this, two studies were conducted to determine the effect of sprouting sorghum grain on the chemical composition of sprouted sorghum and bird performance fed on the HSF based diet. In the first study, sorghum grain was sprouted in a hydroponic system for 168 hours and sampled for proximate analysis, minerals, anti-nutritional factors and amino acids. The sprouted sorghum seeds were subjected to proximate analysis in duplicate samples at 0, 24, 72, 120 and 168 hours. Whereas, in the second study the aim was to assess the effect of sprouted sorghum hydroponic fodder-based diets on growth performance, feed intake, feed conversion ratio, carcass yield and digestibility using Sasso chickens. In the second study one hundred and forty-four, growers were allocated randomly to four dietary treatments with three replications for each diet. Each replicate had 12 chickens. The treatment diets were designated as T1: Control; formulated ration with no fodder, T2: 25% HSF: 75% formulated ration, T3: 50% HSF: 50% formulated ration and T4: 75% HSF: 25% formulated ration. The HSF used in this experiment was that which was sampled for 168 hours. The formulated diets were based on locally available low-cost ingredients. Data collected were body weight, feed intake, digestibility and mortality rate. The digestibility trial was conducted at the end of the feeding trial. Three randomly sampled birds were iii slaughtered from each treatment at the end of 13th weeks and evaluated for dressing percent, weights of components (breast, thigh, and drumstick), the weight of non-carcass components and carcass weight. The results in the first study revealed an increase in CP CF, Ash, EE and decrease in NFE from 12.47 to 17.43%; 2.42 to 5.57%; 1.8 to 2.2%; 2.03 to 2.44% and 71 to 60.77% respectively with an increase in sprouting time. However, the DM content declined from 90.56 to 88.09 % with increased sprouting time. There was a decreasing trend for mineral elements with increase sprouting time. Similarly, there was a corresponding decline for anti-nutritional factors with increased sprouting time. The decline ranged from 4.26 to 1.77 g/100g; 4.94 to1.64 mg/Kg; 6.19 to 1.17 µg/100g and 26.46 to 1.07 g/100g for tannin, cyanide, phytic acid and phenols respectively at 168 hours. The maximum reduction of tannin, phytic acid, total phenol and cyanide was achieved between 72 and 120 hours. The results further showed a corresponding increase in the percentage of amino acid, the percent increase of methionine, lysine, and tryptophan ranged from 0.12 to 0.59, 0.22 to 0.79 and 0.08 to 0.16 respectively with sprouting time. Results in the second experiment showed significant treatment effects on all measured variables. Further increase in HSF inclusion resulted in a declined in body weight gain. The decline ranged from 1970 to 1113.96 g, 6847.39 to 6153.67g, and 3.69 to 6.83 for weight gain, total feed intake, and feed conversion ratio respectively. There was a significant difference (p< 0.005) between treatments on live weight and carcass components. Apparent digestibility of sprouted sorghum decreased from 76.08% to 64.24%, while true digestibility decreased from 72.81% to 64.1%. This study concludes that sprouting increases the nutritive value of HSF and led to a significant reduction of anti-nutritional factors. However, the performance of chickens was depressed when the iv quantity of HSF was increased beyond 25%, due to the lowering of the energy: protein ratio. Thus, the use of HSF should, therefore, be limited but where maize grain availability is limited then, sprouted sorghum can be included at a rate not exceeding 25% as energy sources.