MSUIR Collection:

Effect of processing method on phorbol esters concentration, total phenolics, trypsin inhibitor activity and the proximate composition of the Zimbabwean Jatropha curcas provenance: A potential livestock feed

Chivandi E. — 2004-01-01T00:00:00Z

Title: Effect of processing method on phorbol esters concentration, total phenolics, trypsin inhibitor activity and the proximate composition of the Zimbabwean Jatropha curcas provenance: A potential livestock feed Authors: Chivandi E.; Mtimuni J. P.; Read J. S.; Makuza S. M. Abstract: In a study to detoxify Jatropha curcas seed four potential detoxification methods were tested for their effectiveness. The first method entailed oil expulsion from unshelled Jatropha curcas seed using a Sunhdra industrial oil expeller. The second method involved laboratory-based petroleum-ether solvent extraction of shelled and minced kernels. Thirdly, shelled kernels were subjected to industrial detoxification that involved double solvent extraction with the hexane-ethanol system accompanied by moist-heat treatment at 90°C for 30 min. The fourth method was an extension of the third whereby the meal generated was wet extruded (126°C, 2 atmospheres, 10 min contact time) followed by re-extraction with hexane and moist heat treatment (121°C for 30 min). The detoxification methods had significant (P<0.0001) effect on both the anti-nutritional factors (ANFs) and the proximate composition of the meals. Oil expulsion left the phorbol esters (PEs) of the unshelled seed at 0.70 mg g -1, laboratory petroleum-ether extraction reduced the PEs content by 67.69% from 6.5 mg g -1 in the raw shelled kernels to 2.10 mg g -1, double solvent extraction followed by moist-heat treatment reduced PEs by 70.77% to 1.90 mg g -1. Double solvent extraction accompanied with wet extrusion, re-extraction with hexane and moist-heat treatment reduced PEs content to 0.80 mg g -1, an 87.69% decrease. All the methods except laboratory petroleum-ether solvent extraction managed to completely inactivate trypsin inhibitors in the meals. Total phenolics (TPs) content was lowest (P<0.0001) in the oil-expulsion produced meal (8.50 g Kg -1) while the laboratory petroleum-ether produced meal contained 64.57 g Kg -1 TPs. Oil-expulsion and double solvent extraction accompanied with wet extrusion, re-extraction and moist-heat treatment completely inactivated lectins in the meals. The high chemical nutrient potential of Jatropha curcas seed (crude protein, calcium and phosphorus) is only realised with shelling and extraction of most of the oil. None of the tried methods managed to completely detoxify the Jatropha curcas seed. The two most ‘effective methods’ reduced the PEs to 0.70 and 0.80 mg g -1, respectively compared to the non-toxic variety with 0.11 mg g -1 PEs.

Environmental factors affecting milk production in the Holstein-Friesian population of Zimbabwe

Kunaka K. — 2005-01-01T00:00:00Z

Title: Environmental factors affecting milk production in the Holstein-Friesian population of Zimbabwe Authors: Kunaka K.; Makuza S. M. Abstract: The milk production of a cow is a result of the interaction of both genetic and environmental factors. Lactation records for calvings from 1979 to 1998, from Zimbabwe Dairy services Association were used to estimate the effects of the non-genetic effects on milk production. The model fitted had the fixed effects of herd, season of calving, parity and days in milk. Herd effects were significant (< 0.001). The effect of herd was found to be ranging from 14 to 47% of the total variation in the records. The contribution of the herd on fat and protein percent was lower compared to the contribution to yield traits. Month of calving had a significant effect on milk, fat and protein yield (<0.0001), but had no effect on fat percent and protein percent. The highest yields were in the months of May to August. The Temperature Humidity Index (THI) ranged from 55.95 to 67.78, which is within the range for breed in under study. It had no effect on protein percent. Milk production increased up to parity 5. Protein percent increased from parity one to parity two and then remained almost constant. Fat percent declined from parity one. Milk production and component production increased with increasing days in milk. However, days in milk had no significant effect on fat percent and protein percent. The effect of days dry, days open and calving interval were not studied as they were serious confounding effects which made it impossible to estimate the effects of each one of them. The results indicate that outside economic constraints Zimbabwe can produce milk without the need for strong environmental modifications.

Genetic and environmental trends for milk traits in the Zimbabwean Holstein-Friesian population

Kunaka K. — 2005-01-01T00:00:00Z

Title: Genetic and environmental trends for milk traits in the Zimbabwean Holstein-Friesian population Authors: Kunaka K.; Makuza S. M. Abstract: The data was obtained from the Zimbabwe Dairy Services Association. Genetic trends for milk yield, fat yield and protein yield were estimated using 30, 395 records of cows in parities 1 to 8 using AIREML procedures for cows born 1973 to 1994. Environmental trends were estimated as the difference between the phenotypic and genetic values. The heritabilities for milk yield, fat yield and protein yield was 0.23, 0.21 and 0.21, respectively. The annual genetic trends ranged from 8.72 to 14.40 kg for milk yield and 0.285 to 0.44 kg for fat yield. The annual genetic trends for cows born 1987 to 1994 were higher at 22.39 kg for milk yield, lower for fat yield at 0.127 and 0.39 kg for protein yield. The effects of the droughts were clear from the environmental trends obtained. Also the harsh economic climate in Zimbabwe has led to the negative environmental trends. There were positive genetic trends in milk yield traits that indicate that the dairy cattle genetic improvement strategies that were used in Zimbabwe in the last twenty years were effective.

Effects of dietary substitution of ordinary maize meal with quality protein maize meal on the performance of broiler chicken

Mushipe J. — 2017-03-15T00:00:00Z

Title: Effects of dietary substitution of ordinary maize meal with quality protein maize meal on the performance of broiler chicken Authors: Mushipe J.; Kunaka K.; Masaka J.; Chivandi E. Abstract: Background and Objective: Quality protein maize has a high concentration of essential amino acids compared ordinary maize, hence can be exploited in broiler chicken production. We investigated the effects of graded substitution of ordinary maize (NMM) meal with Quality Protein Maize meal (QPM) on the performance of broiler chicken. Methodology: About 225 day-old Ross Breeders broiler chicks were randomly assigned to five grower-starter diets (SD1-SD5) wherein QPM replaced NMM at 0, 25, 50, 75 and 100% and fed for 4 weeks. The birds were transferred onto similarly constituted corresponding finisher diets; FD1-FD5. Growth performance, carcass yield and gastrointestinal (GIT) macro-morphometry were determined. Results: At 28 days chicks fed QPM-based starter-grower diets were heavier, had higher Body Mass Gain (BMG) and Average Daily Gain [ADG, (p<0.05)]. At 56 days birds fed finisher diets FD4 and FD5 were the heaviest with the highest BMG (p = 0.0002). From 29-56 days birds fed finisher diets FD4 and FD5 had the highest (p<0.05) ADG. Birds reared on SD5 and finisher diets FD5 had the most economic FCR (p = 0.0002). Overall, BMG and ADG were highest (p = 0.0001) in birds fed starter-grower diets SD4 and SD5 and transferred to finisher diets FD4 and FD5. Despite their high FI (p = 0.0084), birds reared on SD5 and transferred to FD5 were the most efficient feed utilizers (FCR = 1.67±0.02, p = 0.0016). Dressed mass increased (p = 0.0001) with dietary QPM. Feeding starter (SD3-SD5) and finisher (FD3-FD5) diets caused longer GIT (p = 0.0001) while feeding starter (SD4-SD5) and finisher (FD4-FD5) diets caused the heaviest livers (p = 0.0005). Conclusion: The QPM increased the growth performance, feed efficiency and carcass yield of broiler chicken.