An In Vitro Evaluation of the Capacity of Local Tanzanian Crude Clay and Ash-Based Materials in Binding Aflatoxins in Solution.

Aflatoxins in feeds cause great health hazards to animals, and thus eventually to humans as well. The potential of clays from Arusha (AC), Kilimanjaro (KC), the Coast (CC), and Morogoro (MC), as well as volcanic ash (VA) and rice husk ash (RA), were evaluated for their capacity to adsorb aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1), and G2 (AFG2) relative to a commercial binder Mycobind® (R) using in vitro technique. On average, CC, VA, KC, MC, AC, RA, and R adsorbed 39.9%, 51.3%, 61.5%, 62.0%, 72.6%, 84.7%, and 98.1% of the total aflatoxins from solution, respectively. The capacity of AC and RA was statistically (p < 0.05) better in binding aflatoxins next to R. The adsorption capacity seemed to follow the trend of the cation exchange capacity (CEC) of these materials. The CEC (meq/100 g) of CC, MC, KC, VA, AC, RA, and R were 7.0, 15.4, 18.8, 25.4, 27.2, 27.2, and 38.9, respectively. On average 96.3%, 42.7%, 80.8%, and 32.1% of AFB1, AFB2, AFG1, and AFG2 were adsorbed, respectively. The binding capacity of the clays and ashes relative to Mycobind® was about 100% for AC and RA, 50% for KC, MC, and VA, and 33.3% for CC. The AC and RA seem to be promising resources in binding aflatoxins in solution.

Rumen liquor from slaughtered cattle as inoculum for feed evaluation.

Use of nonlinear mathematical models has been majorly based on in vitro gas production (GP) data generated when substrates are incubated with rumen liquor from fistulated steers. However, existing evidence suggests that rumen liquor from slaughtered cattle of unknown dietary history also generates quantifiable in vitro GP data. Fitting and description of GP data obtained from 4 diets incubated with rumen liquor from slaughtered cattle was evaluated using single-pool exponential model with discrete lag time (EXPL), logistic (LOG), Groot's (GRTS) and Gompertz (GOMP) models. Diets were formulated by varying proportions of Rhodes grass (Chloris gayana) hay and a concentrate mixed on dry matter basis to be: 1,000 g/kg Rhodes grass hay (RGH) and 0 of the concentrate (D1), 900 g/kg RGH and 100 g/kg concentrate (D2), 800 g/kg RGH and 200 g/kg concentrate (D3), 700 g/kg RGH and 300 g/kg concentrate (D4). Dietary kinetics for the models were determined by measuring GP at 2, 4, 8, 10, 18, 24, 36, 48, 72, 96 and 120 h. Model comparison was based on derived GP kinetics, graphical analysis of observed versus predicted GP profiles plus residual distribution and goodness-of-fit from analysis of root mean square error (RMSE), adjusted coefficient of determination (Adj-R2) and Akaike's information criterion (AIC). Asymptotic GP, half-life and fractional rate of GP differed (P < 0.001) among the 4 models. The RMSE, Adj-R2 and AIC ranged from 1.555 to 4.429, 0.906 to 0.984 and 2.452 to 15.874, respectively, for all diets compared across the 4 models. Based on the goodness-of-fit statistical criterion, GP profiles of D1 were more appropriately fitted and described by GRTS and GOMP than the EXPL and LOG models. The GRTS model had the lowest AIC value for D2 (2.452). Although GRTS model had the most homogenous residual dispersion for the 4 diets, all the 4 models exhibited a sigmoidal behavior. Therefore, rumen liquor from slaughtered cattle of unknown dietary history can be used to derive nutritionally important feed parameters, but choice of the most appropriate model should be made based on fitting criteria and dietary substrates incubated.

Influence of age at entry and level of concentrate feeding on growth and carcass characteristics of feedlot-finished Tanzanian long-fat-tailed sheep.

A 4×3 factorial experiment was carried out to evaluate the effects of age at entry to feedlot (AEF) and levels of concentrate feeding (LCF) on body weight gain, feed utilization and killing out characteristics of Tanzanian long-fat- tailed castrate sheep. The AEF points were 9, 12, 15 and 18 months, designated as AEF9, AEF12, AEF15 and AEF18, and the LCF were 50, 75 and 100 % of ad libitum concentrate intake designated as LCF50, LCF75 and LCF100, the last representing ad libitum concentrate intake with 10 % refusal rate. Grass hay as basal diet was offered ad libitum to each sheep. Daily feed intake and weekly live weight were recorded for a period of 84 days. Animals were slaughtered and carcass and non-carcass parameters were recorded. Dry matter intake (DMI) of hay decreased while DMI of concentrate increased (p<0.01) with increasing LCF. Daily gain in high level (LCF100) was 93.1 g/day, almost twofold higher than that in low level (LCF50) of feeding (39 g/day). Overall dressing percentage ranged from 40.7 to 46.5% and increased with increasing AEF. The proportion of carcass bone decreased (p<0.05) with increasing AEF while that of fat increased (p<0.05) with increasing LCF. Age at entry × level of concentrate feeding interaction was detected for DMI, feed conversion ratio (FCR), slaughter body weight (SBW), muscle/bone ratio and bone (as % cold carcass weight (CCW)), but the effect was not regular. Entering fattening at 18th month seems too late, hence to get in the shortest time the highest output slaughter and carcass weights, fattening should start latest at 15 month.

Preliminary evaluation of slaughter value and carcass composition of indigenous sheep and goats from traditional production system in Tanzania.

The aim of the pilot study was to evaluate slaughter characteristics and carcass composition of indigenous long fat tailed sheep and Small East African goats purchased from the auction markets slaughtered at 1.5 to 2 yrs of age and 20 kg to 25 kg live weight. The animals were slaughtered according to halal standard procedures. The left half carcasses were jointed into eight wholesale joints, and dissected into muscles, fat and bone, which were weighed separately. Sheep had greater (p<0.05) slaughter BW (22.29 kg vs 20.50 kg) and empty BW (20.17 kg vs 18.67 kg) than goats (p<0.05). Dressing percentages were lower (p<0.001) in sheep than goats when carcass weight was expressed as percentage of slaughter BW (42.31% and 47.15%) and empty BW (46.75% and 51.79%). Sheep carcasses had lower (p<0.001) proportion (66.18% vs 71.64%) of muscles and higher (p<0.001) proportion of fat (7.41% vs 3.44%) than goat carcasses. Sheep had proportionally lighter (p<0.001) shoulder (18.89% vs 22.68%) and heavier (p<0.05) proportion of chump (7.916% vs 6.76%) and main rib (8.12% vs 7.07%). Sheep had more (p<0.001) muscles in the leg (28.83% vs 27.08%) and main rib (7.62% vs 6.36%) than goats. Sheep had less (p<0.001) muscles (20.28% vs 23.56%) in shoulder joints when expressed as percentage of total muscle of carcasses. It is concluded that there are differences in sheep and goat both in terms of carcass and joint yields and composition. The present study also implies that there is need to consider setting different meat cuts and prices for these cuts when one takes into account the differences in muscle distribution within joints in sheep and goats.

Chemical composition and meat quality attributes of indigenous sheep and goats from traditional production system in Tanzania.

The aim of the study was to compare chemical composition and quality attributes of meat between male long fat tailed sheep (n = 17) and Small East African goats (n = 17) existing in Tanzania. Animals of 1.5 to 2 yrs in age and live body weight of 22.59±0.50 kg were purchased from livestock auction markets. Animals were fasted for 18 h and slaughtered according to standard halal procedure. Left carcasses were dissected into muscles, fat and bone and the muscle and fat were mixed together and chemically analysed. Meat quality attributes were measured based on Muscle longissimus thoracis et lumborum excised from right sides of carcasses. Goat carcasses had significant higher (p = 0.0302) moisture content (70.65% vs 66.96%) and lower (p = 0.0027) ether extract (2.49% vs 5.82%) than sheep but there was no significant species differences in protein and ash content. Sheep had lower (p = 0.0157) ultimate pH (5.74 vs 5.88) and higher (p = 0.0307) temperature (3.77°C vs 3.15°C) than goat carcasses. Sheep meat had lower (p = 0.0021) shear force values (29.83 N vs 34.07 N) than goat. Within species, at day 9 of ageing, meat tenderness improved (p = 0.0001) by 44.63% and 34.18% for sheep and goat. Pooled data showed that at d 9 of ageing, meat tenderness improved (p = 0.0001) by 39.25% (from 39.54 N to 24.02 N) compared to tenderness of meat which was not aged at day one of slaughter. The present study demonstrated the differences in chemical composition and quality attributes of meat existing between sheep and goats originated from East Africa.