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GENETIC VARIABILITY FOR STEM BORER RESISTANCE IN TWO ADAPTED EARLY-MATURING MAIZE (Zea mays L.) POPULATIONS
Published 2013-03Subjects: “…Maize grain yield…”
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MICROBIAL DEGRADATION OF MAIZE COB AND ITS ASSESSMENT FOR USE AS BROILER FEED SUPPLEMENT
Published 2012-02Call Number: Loading…
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Nutritive potential of sweet potatoes peel meal and root replacement value for maize in diets of African catfish (Clarias gariepinus) advanced fry
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LEAST-COST RATIGNS FOR BROILERS - A LINEAR PROGRAMMING APFROACH
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Page will reload when a filter is selected or excluded.- Broiler 1 results 1
- Clarias gariepinus 1 results 1
- Diets 1 results 1
- Feed stuff 1 results 1
- Genetic gain 1 results 1
- Genetic variance 1 results 1
- Growth 1 results 1
- It has been established that Nigeria has a food problem especially where protein intake is concerned. The poultry industry has been identified as the quickest means of expanding protein supply and lowering its cost within the short run (10-12 weeks for broilers). However, feeds account for 65-75 percent of the total costs of production. Moreover, the numerous problems facing the feed industry coupled with the poor quality of feeds produced have greatly limited the profitability and rapid expansion of the industry. The linear programming (L.P.) tool was utilized to formulate least-cost diets which made use of locally available ingredients. The scarcity and rising costs of the grains (maize and guinea-corn) which provide over 60 percent by weight of broiler feeds prompted the use of cassava flour as an energy providing Substitute. Feeding trials were carried out to test the efficiency of the least-cost diets. The objectives of the study are (1) To use L. P tool to formulate different least-cost rations which meet specific nutritional specifications for broilers, using readily available feed ingredients. Cassava and soya-bean are being tested as energy and protein providing substitutes respectively. (2) To compare the least-cost formulated diets with the diets used by some commercial farms. (3) To find the optimum killing age/weight. (4) To find the rate of Substitution of cassava flour for maize and guinea-corn in the ration for broilers. (5) To determine the economics of using different levels of cassava flour in the rations for broilers. Experimental results showed that starter diets with 24 percent Protein and 5 percent fibre level were better than those with 26 percent protein and 3 percent fib re levels. The computerised starter and finisher diets tested were cheaper and were found to perform better than the commercial diets. For the cassava based diets, analysis of the experimental results showed significant (P < 0.01, P < 0.05, differences in Feed Conversion Efficiency (F.C.E.) in both starter and finisher diets in which guinea- corn and maize were replaced. For weight gain, significant (P 0.01) differences were found only in Starter and finisher diets in which cassava replaced maize. For feed intake, significant differences (P < 0.0l) occurred only in Starter diets in which cassava replaced maize. The diets that caused significant differences were those in which the cassava contents were very high (25-40 percent) and they performed poorest. Even though growth is suppressed due to reduced feed intake caused by the powdery nature of the feeds, it is pertinent to note that diets with 40 percent cassava are still highly tolerable to the birds. Analysis of the weight response as cassava level increases showed that the decrease in weight gain was more rapid when cassava was being substituted for by maize rather than by guinea-corn. This could be attributed to the availability of nutrients or the amino-acid balance of the guinea-corn based diets. Carcass qualities of the birds were not taken into consideration because they are not highly rated in this society. The diets were further investigated to see how the nutrients contents and energy-based ingredients influenced performance, using the multiple linear regression model. The square root and quadratic functions were fitted but the quadratic forms gave the lead equations using the laid down criteria. Feed, protein, energy and the amino-acids intakes proved to be significant explanatory variables for the live- weight gain in the birds. Marginal Analysis was performed on some selected functions. The elasticity of production for energy and protein showed increasing returns to scale in the Starter and finisher diets at the mean value of inputs. As higher levels of inputs are used, diminishing returns is likely to set in. The elasticity of Substitution exhibits a unitary one also at the mean value of inputs. A percentage increase in the energy content of the feed results in an equal percentage decrease in the protein level of the diet. The extent of substitution is limited by the requirement of the birds. Optimum quantities of the energy-based ingredients to produce the Optimum broiler weight gain were determined. Production surfaces, isoquants and isoclines were produced for selected functions of the energy-based ingredients. The rate of Substitution between guinea-com/cassava and maize/cassava were found to be declining with increasing level of output as more of cassava and less of maize or guinea-corn are used. Estimates of revenue over feed costs for the various diets were computed. It was discovered that non-significant differences between diet without cassava was not synonymous with equal revenue yielding diets. In general, the computerised diets without cassava gave higher revenue than the commercial diets. For the diets in which cassava replaced the grains, the revenue accruing to the farmer decreased as the percentage cassava content increased. The revenue from guinea-corn diets were however higher than in the maize diets. Diets with 10 percent cassava had higher or equal revenue with the commercial diets. Diets with higher cassava levels were costlier because cassava is costlier than the grains. It is however envisaged that prices of cassava may fall in the near future because of increases in production. Revenue from the diets was therefore obtained using varying costs of diets as cassava price varies. When cassava was made to assume the same price with guinea-corn, all the computarised diets except that with 30 percent cassava level had higher revenues than the commercial diets. The revenue increased as the cassava prices were reduced but the diets with 30 percent cassava gave the lowest revenue all the time. Optimum killing age determined suggested that broilers be sold at eleven weeks for most of the diets except those in which five and 10 percent cassava replaced guinea-corn. The implications of this study are that efforts to improve returns — poultry farmers must be focused on the cost and quality of feeds. Particular attention must be paid to cheap sources of protein, carbohydrate and oils. There is a very high potential for the use of cassava if its adoption becomes a reality in the future. Further investigations are necessary in testing the least-cost diets with the existing various breeds of broilers. Comparison can also be made of the use of soya-bean and groundnut cake as a protein providing ingredient in broiler diets. 1 results 1
- Maize cob 1 results 1
- Maize grain yield 1 results 1
- Maize, Zea mays is extensively cultivated in Nigeria with estimated total grain yield of 1.37 million tonnes per year. The maize by-product which includes the cob is readily available. This project was designed to convert maize cob to value-added products in broiler feed through microbial degradation using batch fermentation. One hundred and fifty kilogrammes of maize cob samples were collected from four dump sites in a farmers’ market in Oyo town. Bacteria and fungi were isolated using nutrient agar and potato dextrose agar media respectively. Identification of isolates was done by conventional methods and cellulase enzyme assay carried out by dinitrosalicylic acid method. The isolates with cellulase activities were then used for solid state fermentation. The process was then sealed up in fabricated tanks for bulk fermentation using Bacillus subtilis and Aspergillus niger solely. The derivatives labelled Bacteria Enriched Cob Product (BECP) and Fungi Enriched Cob Product (FECP) were subjected to chemical and microbiological analyses. The BECP and FECP were each substituted at 18%, 50% and 82% inclusions in compounded feeds while commercial feed served as control. These were fed to four-week old broiler chicken for six weeks in a completely randomized experimental set up of seven groups with ten chicks per group. Mean Weight Gain (MWG), Feed Conversion Ratio (FCR), economic performance, haematological indices and organ histopathology were determined. Data was analysed using inferential statistics at p = 0.05. Thirty-three (33) isolates made up of 19 bacteria and 14 fungi had cellulase activity. These were the genera Bacillus (10), Pseudomonas (8), Proteus (1) Aspergillus (6), Penicillium (4), Rhizopus (1), Mucor (1), Botryotrichum (1) and Geotrichum (1). The best cellulase producers were Aspergillus niger, 1.7 mg/ml and Bacillus subtilis 0.7 mg/ml with optimal activity at 40oC, pH 4.0 and 28oC, pH 7.0 respectively. Cellulose degradation ability of fungi 17.3% was higher than bacteria 6.6% while the crude protein levels were 7.5% and 9.5% respectively. The MWG (18.0g) of chicks fed BECP (82%), was much lower than the control (34.3g), FECP (18%), 38.9g; BECP (18%), 37.6g; FECP (50%) 31.0g and BECP (50%), 30.7g. The feed cost per kilogram gain for FECP (28%), N185.7; BECP (18%), N208.4 and FECP (50%) N227.4 were lower than the control N235.9. The FCR for BECP (82%), 8.4 was higher than the control value of 3.6. The red blood cell count for all treatments (1.7 – 2.6 x 106/mm3) did not differ significantly. However, white blood cell count was significantly higher in chicken fed with 82%, BECP (27.2 x 103/mm3) and 82% FECP, 20.4 x 103/mm3 compared to the other diets (11.2 – 16.2 x 103/mm3). Only the kidneys and lungs of chickens fed with 82% BECP were severely congested. Maize cob contained cellulolytic bacteria and fungi capable of degrading it at different extents. Substitution of either bacteria enriched product or fungi enriched product up to 50% were economically suiTable and safe for use as broiler chicken feed supplement. 1 results 1
- Microbial degraded cob 1 results 1
- Plant resistance 1 results 1
- Stem borers 1 results 1
- Stem borers are among the major biotic stresses limiting the grain yield of maize, an important cereal crop in Africa. Breeding for multiple resistance to maize stem borers has been reported to be a promising method of control. Understanding the genetic variability of crop populations will help in improving them for pest resistance. Thus, genetic variability for dual resistance to two stem borer species were determined in a white (DMR ESR-W) and a yellow (DMR ESR-Y) maize populations to provide information required for improving their levels of resistance to the borers. Two experiments were conducted. In Experiment 1, a set of 100 S1 plants of DMR ESR-W were selected to produce 250 full-sib and half-sib progenies using the North Carolina Design II (NCD II) mating scheme. The progenies with six checks were evaluated under artificial infestation with two borer species (Sesamia calamistis and (Eldana saccharina) at Ibadan, and non-infested conditions at Ibadan and Ikenne in 2008 and 2009 using Randomized Incomplete Block Design with two replications. Experiment 2 was with DMR ESR-Y and the same methodology was used. In both experiments, days to 50% anthesis and silking, plant and ear height, plant and ear aspect, ear length and grain yield were measured. Resistance was measured according to levels of leaf feeding damage, dead heart, stalk breakage, cob damage and stem tunneling. Analyses of variance for NCD II were conducted to estimate genetic variances and Narrow-Sense Heritability (NSH). Correlation coefficients were determined and partitioned into direct and indirect effects. Predicted responses to selection were estimated to measure expected genetic gains. Correlated response was used to determine traits that could hasten selection progress. Tests of significance were conducted at p < 0.05. Infestation significantly reduced plant height (6.0 -11.1%), ear length (20.9 - 25.6%) and grain yield (23.9 - 30.4%) in both maize populations. Additive variance was significant for grain yield and stalk breakage in DMR ESR-W, and for stalk breakage, cob damage and stem tunneling in DMR ESR-Y. Narrow-sense heritability was low to moderate, but low for damage parameters except stalk breakage (40.6%) in DMR ESR-W, and cob damage (40.1%) in DMR ESR-Y. Negative correlations exist between grain yield and increasing levels of stem borer damage, with genotypic correlation between grain yield and stem tunneling being the highest (-0.52*) in DMR ESR-Y. Stem tunneling and cob damage had high positive direct effects on grain yield reduction. Estimated genetic gain per generation was 4.0 - 6.1% (= 210kg/ha) for grain yield under infestation in DMR ESR-W, but low for damage parameters in both maize populations. Direct selection for individual trait gave better response than indirect selection through other traits. The significant additive variances and moderate heritability estimates obtained for stalk breakage and cob damage indicate that the traits are heritable, therefore, improvement of the maize populations for stem borer resistance using these traits is feasible. Direct selection for grain yield is recommended in improving the maize populations. Stem tunneling and cob damage by the borers are major causes of grain yield reduction. 1 results 1
- Sweet potato 1 results 1
- This study was carried out to evaluate the potential of Sweet Potato Peel (SPP) meal as a cheaper replacement for maize in the diet of Clarias gariepinus. Triplicate groups of 20 fish per plastic tank with average weight of 0.64±0.1 g per fish were fed four (4) diets, which were formulated to contain graded levels of sweet potato peel meal replacing 0, 25, 50 and 75 % of maize. The feeding trial lasted 6 weeks. The results showed that the diets did not significantly (p<0.05) affect fish performance within the treatments. Percentage Weight Gain (PWG) was 101.54% in fish fed with the control diet (0% sweet potato peel meal). The highest (PWG) of 150.77% was recorded in fish fed diets containing 25% sweet potato peel meal followed by a consistent decrease in PWG with increasing inclusion of sweet potato peels meal. However, diets containing 25, 50 and 75% SPP meal performed better than the control experiment with PWG of 150.77, 132.31 and 127.6%, respectively. The highest Feed Conversion Efficiency (FCE) was observed in the diet containing 25% SPP meal. A steady decrease in FCE was observed with increasing inclusion of SPP meal at 50 and 75%. Meanwhile, all the diets with SPP meal inclusion performed better than the control diet containing 0% SPP. The data indicated that Clarias gariepinus effectively tolerated diets containing sweet potato peel meal at low levels of concentration while fish growth performance and utilization decreased with increase in the sweet potato peel meal inclusion. The SPP meal based diets were cheaper than the control diet. The consequent better FCE and PWG of fish fed SPP diets showed that cost can be reduced while maintaining a high yield. 1 results 1
- Utilization 1 results 1
- |Incidence of cost 1 results 1
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