A qualidade da carne produzida pelos ruminantes é um reflexo do alimento consumido pelos mesmos. Primeiramente realizamos uma abordagem metanalitica e verificamos que o tipo de sistema alimentar e o nível de tocoferol na dieta dos cordeiros enfluinciaram na qualidade da carne de cordeiro produzida. Assim, o objetivo foi avaliar a produção de forragem e composição química da dieta dos cordeiros alimentados com pastagens tropicais e seus reflexos sobre a qualidade da carne. Foram utilizamos 54 cordeiros, machos castrados, com idade e peso inicial de 3-4 meses e 20,4±3,97 kg, distribuídos aleatoriamente em três sistemas de terminação baseados em pastagens tropicais: 1) Capim aruana (Panicum maximum cv. IZ-5); 2) Feijão guandu (Cajanus cajan) e 3) Consórcio (Panicum máximo cv. IZ-5 e Cajanus cajan, sendo cada espécie semeada em metade da superfície do piquete. Para testar o efeito tanino, metade dos cordeiros de cada tratamento recebeu polietilenoglicol (PEG) duas vezes ao dia. A amostragem da pastagem foi realizada a cada 21 dias, totalizando 4 coletas. Foi reaizada simulação de pastejo para as amostragens para composição química da pastagem. Avaliou-se a produção de forragem, composição química, perfil de ácidos graxos e antioxidantes (tocoferol e taninos). Os cordeiros foram abatidos após 92 dias de experimento, com peso médio de 25,7±4,36 kg O perfil de ácidos graxos, concentração de tocoferóis, a coloração e a oxidação lipídica do músculo longissimus dos cordeiros foram avaliados. As pastagem apresentaram variação de masa de forragem, produção de colmos, produção de lâminas foliares e altura ao longo do tempo da avaliação. A inserção de leguminosas na dieta de cordeiros não altera a concentração de tocoferol, mas, ao longo dos períodos de avaliação, os níveis de tanino condensado e tanino total aumentam na dieta contendo leguminosas. A maioria dos acidos graxos estavam relacionados com o conteúdo de fibra em detergente neutro da dieta. A participação da leguminosa na dieta dos cordeiros aumenta o teor de omegas 3 e 6 disponíveis na dieta de cordeiros. A inclusão de PEG nas dietas dos cordeiros aumentou o valor do ângulo da tonalidade e diminuiu a intensidade de vermelho da gordura subcutânea. O sistema de pastagem exclusivamente de feijão guandu resultou em menor concentração de ácidos graxos saturados no musculo do que o sistema exclusivo de capim aruana. A carne de cordeiros terminados exclusivamente em Capim Aruana apresentou menor relação n-6: n-3 e menor oxidação lipídica após 6 dias de armazenamento do que animias mantidos em feijão guandu ou em pastagem consorciada. / The quality of the meat produced by ruminants is a reflection of the food consumed by those offered to them. First, we performed a meta-analytic approach and found that the type of food system and the level of tocopherol in the diet of lambs influenced the quality of the lamb meat produced. We used 54 male lambs with age and initial weight of 3-4 months and 20.4 ± 3.97 kg randomly distributed in three finishing systems based on tropical pastures: 1) Aruana grass (Panicum maximum cv. IZ-5); 2) Pigeon pea (Cajanus cajan) and 3) Consortium (Panicum maximum cv. IZ-5 and Cajanus cajan, each species being sown on half of the surface of the picket. To test the tannin effect, half of the lambs from each treatment received polyethylene glycol (PEG) twice daily. Pasture sampling was performed every 21 days, totaling 4 collections. Grazing simulation was performed for the chemical composition of the pasture. The forage production, chemical composition, profile of fatty acids and antioxidants (tocopherol and tannins) were evaluated.The lambs were slaughtered after 92 days of experiment, with weight of 25.7 ± 4.36 kg . The fatty acid profile, concentration of tocopherols, coloration and lipid oxidation of lamb longissimus muscle were evaluated The present variation pasture forage mass, stalk production, production of leaf blades and height throughout the evaluation time The insertion of legumes in the diet of lambs does not alter the concentration of tocopherol, but during the evaluation periods, , the levels of condensed tannin and total tannin increase in the diet containing legumes. Most of the fatty acids studied were related to the neutral detergent fiber content of the diet. The participation of the legume in the diet of lambs increases the content of omegas 3 and 6 available in the diet of lambs. The inclusion of PEG in lamb diets increased the value of the hue angle and decreased the red intensity of the subcutaneous fat. The grazing system exclusively of pigeon pea resulted in a lower concentration of saturated fatty acids in the muscle than the exclusive system of Aruana grass. Meat from lambs exclusively in Aruana grass presented lower n-6: n-3 ratio and lower lipid oxidation after 6 days of storage than those maintained on Pigeon pea or Mixed pasture.

Thesis (M.Sc. (Agriculture Agronomy)) -- University of Limpopo, 2020 / Pigeonpea (cajanus cajan [L] Millsp.) is a legume crop which is grown mainly in the Semi-Arid Tropical (SAT) regions and it is mostly cultivated for its edible seeds. It has been identified as a possible substitute crop which can be bought by all people and it can also provide an acceptable amount of nutrition and protein in particular as it is not an expensive source of protein when compared to animal protein. Its ability to tolerate drought and fix atmospheric nitrogen makes it suitable for marginal areas with low rainfall and poor fertility. However, it remains one of the underutilized crops due to limited research on the crop’s diversification and adaptation. Smallholder farmers in the Limpopo Province cultivate landraces pigeonpea varieties that are characterized by late maturity, low grain yield and are sensitive to photoperiod and this makes it difficult for the cultivars to flower early and produce reasonable yield. The objectives of the study were to evaluate the nitrogen fixation, yield and yield components of exotic elite pigeonpea genotypes. The experiment was conducted at the University of Limpopo Experimental farm (Syferkuil) in Mankweng during the 2017/18 growing seasons. The trial was carried out in a Randomized Complete Block Design (RCBD) consisting of three replications. A total of 18 elite pigeonpea breeding lines obtained from ICRISAT in Kenya were planted at an inter-row and intra-row spacing of 1m and 0.5m respectively, in a row of 5m length with an alley way of 2m between the blocks. The standard management practices for pigeonpea were used for weed and insect control. The agronomic data collected included the number of days to first and 50% flowering, the number of days to 90% maturity, canopy width (m), plant height (m), peduncle length (m), number of primary branches, number of pods per plant, pod length (cm), hundred seed weight (g), calcium content, sodium content, magnesium content, phosphorus content, potassium content, iron content, zinc content, proportion of legume N derived from the fixation of atmospheric N2 (%Ndfa), amount of nitrogen fixed and the grain yield (kg.ha-1 ). The generated data was subjected to an analysis of variance using the Statistix 10.0 software. The Least Significance Difference (LSD) was used to separate the means that showed significant differences at an alpha level of 0.05. The results revealed significant differences in nearly all the pigeonpea variables (pod length, number of seed per pod, nutrient elements and the number of primary branches). Across genotypes, the number of days to 50% flowering ranged from 95 to 130 days, while the number of days to 90% maturity ranged from 172 to 220 days, with variety ICEAP 01154-2 being the earliest to flower and mature. Tall plants were observed by variety ICEAP 01541 (2.01m) followed by ICEAP 00902 (1.99m) and ICEAP 00850 (1.90m). Breeding line ICEAP 00673-1 recorded long peduncles with a mean of 0.94m. The number of pods per plant had a range between 56 and 482, while the pod length varied from 2.03 to 8.82cm. Variety ICEAP 00673-1 exhibited the highest number of pods per plant and with longest pods. The 100 seed weight varied from 9.43 to 16.97g among the genotypes. The higher calcium amount was observed in verities ICEAP 00979-1 with an average of 556 mg/L and the highest iron content was observed in ICEAP 01172-2 (14 mg/L). The potassium content ranged between 24 mg/L to 110 mg/L, with the variety ICEAP 00540 having the highest and the variety ICEAP 00850 having the lowest content. The sodium content ranged from 15 to 85.1 mg/L, with the variety ICEAP 01154-2 being the highest and the variety ICEAP 01147-1 having the lowest sodium content. The highest magnesium content was observed in ICEAP 00673-1 (141 mg/L). The phosphorus content ranged from 24.5 to 3.77 mg/L and the highest zinc content was observed in ICEAP 01541 and in ICEAP 00979-1 that had an average of 2.36 and 2.26 mg/L, respectively. The amount of nitrogen fixed from all the varieties ranged from 73.547 to 154.254 kg.ha-1 . The grain yield among the genotypes ranged from 89.24 to 785.29 kg.ha-1 . The top yielding varieties were ICEAP 01159 and ICEAP 00557 with grain yields of 785.29 and 661.51 kg.ha-1 . ICEAP 01159 and ICEAP 00557 are the varieties that produced the highest grain yields and they are recommended for cultivation and breeding purposes. / NRF (National Research Foundation)

Pine rocklands are endangered ecosystems unique to south Florida, the Bahamas and Cuba. As a result of their karstic calcium carbonate­rich soil, these systems are limited in phosphorus and nitrogen, making symbiotic associations critical to plant growth. Four leguminous species (Cajanus cajan, Chamaecrista fasciculata, Tephrosia angustissima, and Abrus precatorious) were used to determine the relationship between rhizobial partners and plant performance, and the symbiosis related gene nifH was amplified to characterize the diversity of rhizobial symbionts. Plants were grown in soils from four different south Florida pine rocklands, and a salinity treatment was added to determine how storm surge and sea level rise could affect this symbiotic relationship. While plant performance and nodulation were highly impacted by soil type, salinity did not represent a significant effect. Phylogenetic analysis determined that all four plant species were found to associate with Bradyrhizobium spp. and no rhizobial shift between salinity treatment and soil type was found.