No abstract

A cross-sectional study was conducted to detect the presence of Salmonella spp., Candida albicans, Aspergillus spp., and antimicrobial residues in raw milk (n = 120) and processed cow milk (n = 20) from smallholder dairy farms from three sites in Zimbabwe. Culture and isolation of Salmonella spp., C. albicans, and Aspergillus spp. were performed using selective media, while antimicrobial residues were detected by a dye reduction test. No Salmonella, but C. albicans (17.5%; 21/120), Aspergillus spp. (0.8%; 1/120), and antimicrobial residues (2.5%; 3/120) were detected from raw milk. C. albicans was isolated from all three sites, while Aspergillus spp. and antimicrobial residues were detected from sites 1 and 3, respectively. From processed milk, only C. albicans (5%) was isolated while Aspergillus spp. and antimicrobial residues were not detected. These results suggested low prevalence of Salmonella spp. and Aspergillus spp. and a relatively high prevalence of C. albicans in raw milk from the smallholder farms. The potential public health risks of C. albicans and the detected antimicrobial residues need to be considered. Thus, educating farmers on improving milking hygiene and storage of milk and establishing programmes for monitoring antimicrobial residues may help to improve the safety of milk from smallholder farms.

The effect of A. angustissima leaf meal based diets on intestinal physiology and dressed carcass weight was investigated on 150 day old chicks. Three diets, 0, 5 and 10% A. angustissima were used in a three phase feeding programme. At days 14, 28 and 42, two birds from each replicate were slaughtered, dressed and weighed. The weights and lengths of the duodenum, jejunum and colon were measured. Approximately 1 cm specimen was taken from each organ, fixed in formalin and stained for histological analysis. Using a light microscopy, the digestive and absorptive properties of the tissues were assessed. Inclusion of A. angustissima leaf meal increased intestinal wall thickness, epithelial thickness, and villus height of the duodenum (P < 0.05). There was no effect on the proportional weight and length of the jejunum, jejunum villi height and villi width (P > 0.05) but jejunum wall thickness decreased with increasing levels of the leaf meal (P < 0.05). Leaf meal inclusion resulted in an increase in weight, intestinal wall and mucosal thickness of the colon (P < 0.05) and a decline in sub-mucosal fold height and haustra coli width of the colon (P < 0.05). Dressed weight was the same across diets at two weeks (P > 0.05). At four and six weeks, broilers on the control and 5% diet had superior dressed weights to the 10% fed broilers (P < 0.05). It was concluded that for intestinal physiological adaptation that will not compromise weight gain in broilers, up to 5% A. angustissima could be included in broiler diets.

The objective of the study was to determine serum lipid, enzyme, and hematological responses of broilers to Acacia angustissima leaf meal. Acacia angustissima leaves were harvested at mid maturity, ground into a leaf meal, and included in broiler diets at 0, 5, and 10%. One hundred and fifty-day-old chicks of 41.7 ± 1.560 g were randomly allocated to 15 groups of the three diets. Feed and water were provided ad libitum throughout the trial. At days 14, 28, and 42, 4 ml of blood were collected from the jugular vein in plain vacutainer tubes for alanine aminotransferase (ALT), alkaline phosphatase (ALP), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and total cholesterol (TC) analyses. At the end of the experiment, 4 ml of blood were collected from two randomly selected birds of each replicate in sterilized bottles containing ethylene diamine tetra acetic acid (EDTA) for full blood count and packed cell volume assessment. Data was tested for normality and analyzed using the General Linear Model Procedure of SAS version 9.3 (SAS 2010). Comparison of means was done using Tukey's test. A. angustissima had no effect on serum ALP, AST, LDH, TC, HDL-C, LDL-C, TG, full blood count, and packed cell volume. Increasing levels of A. angustissima leaf meal increased the ALT in the serum (p < 0.05) at 4 and 6 weeks. However, serum ALT indices for birds on the control and 5% diet were not different. It was concluded that 5% A. angustissima leaf meal can be included in broiler diets without a negative effect on serum lipid and enzyme profile, production and proportions of white blood cells and packed cell volume.

The study determined the appropriate levels of including Acacia angustissima leaf meal in broiler diets for optimum performance, carcass part yield, and meat quality characteristics. One hundred and fifty broiler chicks were allocated to 0%, 5%, and 10% A. angustissima leaf meal-based diets in a completely randomized design, with five replicates per treatment. Weekly feed intake and live weights were measured. Weekly weight gains and feed conversion ratios were calculated. At six weeks, two birds per replicate were slaughtered and dressed. Carcass and portion yields were determined. Breast proximate components, CIELAB colour variations, cooking loss and shear force were estimated. Consumer preferences for colour, aroma, taste, flavour and tenderness were determined. Voluntary feed intake (VFI), weekly weight gain, weekly live weights and feed conversion ratios (FCR) were the same across treatments at two weeks. At weeks 4 and 6, the control and 5% groups outperformed the 10% group. Increasing dietary leaf meal had no effect on dressing out percentage, but decreased carcass weight from 1456 g to 1060 g, breast yield from 36.83% to 32.69%, breast meat to bone ratio from 4.77% to 2.94%, and proportion of drumstick skin from 11.57% to 7.92%. It also resulted in increased yield of thighs from 14.63% to 15.97%, proportion of thigh skin from 11.50% to 14.31% and breast skin proportion from 5.37% to 7.95%. The leaf meal had no effect on the proximate components of breast meat. The L* values decreased from 53.66 to 49.23; the b* values increased from 12.93 to 19.97; shear force increased from 14.14 N to 14.54 N; and cooking loss increased from 5.95% to 7.64% with increasing leaf meal levels. It was concluded that up to 5% A. angustissima leaf meal inclusion has no negative effect on performance, yield of carcass parts and meat quality characteristics of broilers.