THE EFFECTS OF INCLUSION OF SILVERLEAF DESMODIUM (Desmodium uncinatum) FORAGE AND MOLASSES ON NAPIER GRASS (Pennisetum purpureum) SILAGE QUALITY

Tropical grasses such as Napier grass (Pennisetum purpureum) have high dry matter yield but are low in protein content. One way of overcoming the low protein of Napier is to combine the grass with herbaceous forage legumes during silage making. Conserving grass-legume forage as silage is an option that alleviates feed constraints during dry periods. The objective of the study was to investigate the fermentation quality and nutritive value of Napier grass ensiled with Silverleaf desmodium (Desmodium uncinatum) forage and molasses as an additive. Existing Napier and Silverleaf forages were harvested, chopped to 2.5 cm pieces and ensiled for eight weeks in mini silos. The legume and grass were mixed in the following ratios 0:100, 20:80 and 50:50, respectively, whilst molasses was added at levels of 3% and 5% (w/w). The pH ranged from 3.86 to 5.03, indicating good fermentation quality of the silage. The best fermentation was observed in 5% molasses and 20% Silverleaf silage which had significantly (P 0.05) differences in the ash and organic matter content of the silages. The crude fibre content was significantly (P > 0.05) high in silages containing higher amounts of Silverleaf. The inclusion of molasses improved the fermentation characteristics of Napier grass silage whilst the inclusion of the legume Silverleaf improved the protein content of Napier grass silage

THE EFFECTS OF INCLUSION OF SILVERLEAF DESMODIUM (Desmodium uncinatum) FORAGE AND MOLASSES ON NAPIER GRASS (Pennisetum purpureum) SILAGE QUALITY

Tropical grasses such as Napier grass (Pennisetum purpureum) have high dry matter yield but are low in protein content. One way of overcoming the low protein of Napier is to combine the grass with herbaceous forage legumes during silage making. Conserving grass-legume forage as silage is an option that alleviates feed constraints during dry periods. The objective of the study was to investigate the fermentation quality and nutritive value of Napier grass ensiled with Silverleaf desmodium (Desmodium uncinatum) forage and molasses as an additive. Existing Napier and Silverleaf forages were harvested, chopped to 2.5 cm pieces and ensiled for eight weeks in mini silos. The legume and grass were mixed in the following ratios 0:100, 20:80 and 50:50, respectively, whilst molasses was added at levels of 3% and 5% (w/w). The pH ranged from 3.86 to 5.03, indicating good fermentation quality of the silage. The best fermentation was observed in 5% molasses and 20% Silverleaf silage which had significantly (P 0.05) differences in the ash and organic matter content of the silages. The crude fibre content was significantly (P > 0.05) high in silages containing higher amounts of Silverleaf. The inclusion of molasses improved the fermentation characteristics of Napier grass silage whilst the inclusion of the legume Silverleaf improved the protein content of Napier grass silage

Effects of sex and stocking density on the performance of broiler chickens in a sub-tropical environment

The current study investigated the effects of sex and stocking density and their interaction on growth performance and carcass characteristics of broiler chickens in a semi-arid sub-tropical environment. A total of 1008 day-old Cobb Avian48 chicks, namely 462 males and 546 females, were reared at final stocking densities of 30, 35, and 40 kg bodyweight per square metre (BW/m2) corresponding to 44, 51 and 59, and 52, 61 and 69 chicks per pen for males and females, respectively, during a 42-day production period. The experiment was a 2 × 3 factorial completely randomized design, with each sex-stocking density combination being replicated three times. After the initial weighing, the birds were weighed individually [grams (g)] each week until the 42nd day. At day 42, four birds from each pen were randomly sampled and slaughtered, and carcass characteristics were measured after 48 hours, and expressed as percentages of bodyweight. Growth performance and carcass characteristic parameters were subjected to analysis of variance using the general linear model procedures of Minitab statistical software version 17. Treatment means were compared using Tukey’s test (at α = 0.05). Males gained more weight and were significantly heavier at slaughter age (2649 ± 43.1 g) than females (2270 ± 43.1 g). There was a progressive reduction in feed intake with increasing stocking density, but neither sex nor stocking density influenced feed conversion ratio and mortality rate. Sex significantly affected dressing percentage and carcass parts percentages, namely breast, neck, shank, heart and abdominal fat and thigh, liver and gizzard. On the other hand, stocking density significantly influenced dressing percentage and carcass parts percentages such as breast, thigh, drumstick, neck, shank, liver and gizzard. There was a significant sex x stocking density interaction effect on percentages of thigh and liver. It is therefore suggested that for efficient 42-day production cycles of broilers in the subtropics, Cobb Avian48 males reared at the stocking density of 40 kg BW/m2 could be considered the best option.Keywords: Carcass characteristics, Cobb Avian48, feed conversion ratio, mortalit

Productivity of Acacia angustissima accessions at two sites in the subtropics

Low leaf biomass yields coupled with small land sizes are some of the major constraints faced by smallholder farmers that grow protein-rich fodder trees and shrubs. Given these challenges, availability of highly productive seed sources would be important to enable farmers to produce leaf fodder in sufficient quantities. 14 accessions of Acacia angustissima were evaluated for leaf, wood and total biomass production at two subtropical sites with uni-modal rainfall in Zimbabwe, with the objective of identifying high leaf biomass yielding accessions. There were up to fourfold difference in biomass yield between the accessions. Leaf dry matter yield ranged from 1.65 to 8.81 Mg ha-1 and 3.7 to 12.4 Mg ha-1 for wood biomass at the higher altitude site (1530 m a.s.l.) but were much lower at 1272 m a.s.l. where they ranged between 0.37 and 4.88 Mg ha-1 for leaf and 0.4 and 7.2 Mg ha-1 for wood. The most productive accessions for leaf biomass were 16231 and 18579 at the higher altitude site, while 18586 and 18501 had the highest yields at the lower altitude. Although no one accession was consistently high yielding across the two sites, the least productive accessions were consistently poor at both sites. The advantage of using selected superior accessions over the unselect bulk seed was up to 85%. These findings underscore the need to promote the use of only high yielding accessions rather than unselect bulk seed. This study identified new, more productive accessions of A. angustissima that potentially widens the genetic base of the germplasm assembled in Zimbabwe.Key words: Leaf biomass, accession, accession × site interaction, Acacia angustissima

THE GROWTH PERFORMANCE, BIOMASS PRODUCTION AND NUTRITIVE VALUE OF THREE MORINGA PROVENANCES IN LUYENGO, SWAZILAND.

Scarcity of animal feed resources, particularly during the dry season, is a major constraint to livestock production in the tropics and in particular in Swaziland. Commercial animal feed supplement are too expensive for most farmers and alternative resources are needed. Moringa oleifera (Lam) has been used as a protein source in feeding livestock. However, its growth performance, biomass production and chemical composition have not been investigated in Swaziland. The study investigated the field growth performance, biomass production and chemical composition of Moringa provenances under Luyengo condition. The Moringa provenances used were Mayiwane, Malawi and Binga in a randomised complete block design with each provenance replicated twice. The plant height and root collar diameter were measured for 23 weeks after field planting. The data was analysed using Statistix Version 2. The root collar diameter for Mayiwane provenance was greater (P 0.05). The increment in root collar diameter followed a similar trend with Mayiwane provenance having an increment of 0.019cm/d compared to 0.012cm/d for Malawi and Binga provenances. Malawi and Binga provenances had similar (P > 0.05) plant height which was lower (P 0.05) different in CP, CF and EE content among the provenances. It can be concluded that the Moringa provenances produce substantial forage biomass and can be used as protein supplements to ruminant and non-ruminant diets in Swaziland

GROWTH PERFORMANCE AND FORAGE NUTRIENT CONTENT OF MORINGA (MORINGA OLEIFERA LAM) PROVENANCES UNDER LUYENGO CONDITIONS, SWAZILAND CONDITIONS

The incorporation of tree and shrub species in animal production systems is a viable alternative to improve the utilisation of land and at the same time improve the diet of livestock. Scarcity of animal feed resources, particularly during the dry season, is a major constraint to livestock production in Swaziland. Therefore, alternative feed resources need to be investigated. Moringa oleifera (Lam) leaves can be used as animal feed. Its growth performance and nutritive value has not been documented in the country. The objective of the study was to determine the growth performance and chemical composition of three provenances of Moringa. The three provenances evaluated were Mayiwane, Malawi and Binga in a completely randomised design with three replications. The Moringa was measured for growth performance for 12 weeks and harvested after 16 weeks for chemical analysis. The plant height for Mayiwane provenance ranged from 8.86 cm to 51.25 cm, Malawi provenance ranged from 6.61cm to 40.79 cm and Binga provenance ranged from 2.71cm to 40.79 cm. Root collar diameter for Mayiwane provenance ranged from 0.196 cm to 0.625 cm, Malawi provenance ranged from 0.144 cm to 0.526 cm and Binga provenance ranged from 0.065 cm to 0.531. The three provenances had significant (P0.05) differences in CP, CF, OM and ash content among the provenances. Mayiwane provenance had the highest DM value of 21.22% and was not significantly different (P > 0.05) from Binga provenance which was 20.72%. It is concluded that Mayiwane provenance can be utilised for its fast growth rate and its adaptability to Luyengo for large scale forage production

Reaction hijacking inhibition of Plasmodium falciparum asparagine tRNA synthetase

Malaria poses an enormous threat to human health. With ever increasing resistance to currently deployed drugs, breakthrough compounds with novel mechanisms of action are urgently needed. Here, we explore pyrimidine-based sulfonamides as a new low molecular weight inhibitor class with drug-like physical parameters and a synthetically accessible scaffold. We show that the exemplar, OSM-S-106, has potent activity against parasite cultures, low mammalian cell toxicity and low propensity for resistance development. In vitro evolution of resistance using a slow ramp-up approach pointed to the Plasmodium falciparum cytoplasmic asparaginyl-tRNA synthetase (PfAsnRS) as the target, consistent with our finding that OSM-S-106 inhibits protein translation and activates the amino acid starvation response. Targeted mass spectrometry confirms that OSM-S-106 is a pro-inhibitor and that inhibition of PfAsnRS occurs via enzyme-mediated production of an Asn-OSM-S-106 adduct. Human AsnRS is much less susceptible to this reaction hijacking mechanism. X-ray crystallographic studies of human AsnRS in complex with inhibitor adducts and docking of pro-inhibitors into a model of Asn-tRNA-bound PfAsnRS provide insights into the structure-activity relationship and the selectivity mechanism.</p

Reaction hijacking inhibition of Plasmodium falciparum asparagine tRNA synthetase

Malaria poses an enormous threat to human health. With ever increasing resistance to currently deployed drugs, breakthrough compounds with novel mechanisms of action are urgently needed. Here, we explore pyrimidine-based sulfonamides as a new low molecular weight inhibitor class with drug-like physical parameters and a synthetically accessible scaffold. We show that the exemplar, OSM-S-106, has potent activity against parasite cultures, low mammalian cell toxicity and low propensity for resistance development. In vitro evolution of resistance using a slow ramp-up approach pointed to the Plasmodium falciparum cytoplasmic asparaginyl-tRNA synthetase (PfAsnRS) as the target, consistent with our finding that OSM-S-106 inhibits protein translation and activates the amino acid starvation response. Targeted mass spectrometry confirms that OSM-S-106 is a pro-inhibitor and that inhibition of PfAsnRS occurs via enzyme-mediated production of an Asn-OSM-S-106 adduct. Human AsnRS is much less susceptible to this reaction hijacking mechanism. X-ray crystallographic studies of human AsnRS in complex with inhibitor adducts and docking of pro-inhibitors into a model of Asn-tRNA-bound PfAsnRS provide insights into the structure-activity relationship and the selectivity mechanism

Reaction hijacking inhibition of Plasmodium falciparum asparagine tRNA synthetase

Malaria poses an enormous threat to human health. With ever increasing resistance to currently deployed drugs, breakthrough compounds with novel mechanisms of action are urgently needed. Here, we explore pyrimidine-based sulfonamides as a new low molecular weight inhibitor class with drug-like physical parameters and a synthetically accessible scaffold. We show that the exemplar, OSM-S-106, has potent activity against parasite cultures, low mammalian cell toxicity and low propensity for resistance development. In vitro evolution of resistance using a slow ramp-up approach pointed to the Plasmodium falciparum cytoplasmic asparaginyl-tRNA synthetase (PfAsnRS) as the target, consistent with our finding that OSM-S-106 inhibits protein translation and activates the amino acid starvation response. Targeted mass spectrometry confirms that OSM-S-106 is a pro-inhibitor and that inhibition of PfAsnRS occurs via enzyme-mediated production of an Asn-OSM-S-106 adduct. Human AsnRS is much less susceptible to this reaction hijacking mechanism. X-ray crystallographic studies of human AsnRS in complex with inhibitor adducts and docking of pro-inhibitors into a model of Asn-tRNA-bound PfAsnRS provide insights into the structure-activity relationship and the selectivity mechanism