Effect of Acacia mearnsii Tannin Extract Supplementation on Reproductive Performance and Oxidative Status of South African Mutton Merino Rams

We investigated the supplementation effects of Acacia mearnsii tannin extract (TE) and encapsulated tannin extract (ETE) on reproductive performance and oxidative status of South African Mutton Merino rams. We also observed the season effect on the testicular measurements. Thirty rams were divided into five groups: 0.0 g TE (control), 1.5 g TE, 3 g TE, 1.5 g ETE, and 3 g ETE supplemented daily for 16 weeks transiting from autumn to winter. Bodyweight and testicular measurements were recorded biweekly. Semen and blood samples were collected weekly during the last five weeks of supplementation. Results showed that the increase in the ETE from 1.5 to 3 g increased the testicular length and sperm concentration, as well as decreased the percentages of low and non-progressive spermatozoa (p<0.05). Simultaneously,the increase in the TE from 1.5 to 3 g decreased semen volume and elevated the percentage of abnormal sperm (p<0.05). The results suggest that the encapsulation of TE affords the maximum benefit of the TE on the sperm quality. Treatments did not affect the hormonal and oxidative status. Testicular measurements were significantly higher in autumn compared to winter. The plasma level of cortisol significantly correlates negatively with sperm motility, viability, and acrosome integrity.

Genetic Variation in Frost Tolerance, Uromycladium acaciae Rust Resistance, and Growth in an Acacia mearnsii Population

Genetic variation in frost tolerance, resistance to the rust fungus Uromycladium acaciae, growth, stem form, and gummosis were evaluated in 110 open-pollinated families of black wattle (Acacia mearnsii De Wild). Families were tested at six frost-prone sites in northern KwaZulu-Natal and southeastern Mpumalanga, South Africa. Frost-hardy provenances were susceptible to rust disease and had poor growth. Locally grown F1 seed sources that originated from cold-hardy Australian seed sources had better growth and were tolerant to rust, but at a cost of lower frost tolerance. Considerable genetic variation was observed between families within seed sources for frost damage (hfm2 = 0.77), rust incidence (hfm2 = 0.89), and height (hfm2 = 0.80). The corresponding narrow-sense heritabilities (hi2) were 0.30, 0.80, and 0.32. Genotype-by-environment interaction levels were low for most traits. Except for a strong genetic correlation between tree height and diameter (0.90), all the pairs of traits had weak to moderate genetic correlations. Recurrent selection will be successful in improving frost tolerance and rust incidence. However, the current population comprises limited germplasm that is both tolerant to frost and resistant to rust. Thus, we recommend infusing germplasm from known cold-hardy Australian provenances into the current population to increase genetic variation for frost tolerance, rust, and growth. Study Implications Black wattle (Acacia mearnsii De Wild) is widely planted in South Africa for bark extract and woodchip exports. The species is prone to frost damage and susceptible to rust fungus Uromycladium acaciae, two major limitations to its cultivation. In this study, 110 open-pollinated families of black wattle originated from its native range in Australia and local South African seed sources were studied for frost and disease tolerance. The results from this study suggest that there is considerable variation within species for frost tolerance and fungal disease. We suggest a tandem selection strategy for black wattle farming in South Africa to increase resistance to frost damage and fungal diseases.

Ajustes de metodologias para quantificações de tânicos em extrato vegetal

RESUMO: Este estudo apresentou como objetivo avaliar o uso do pó de pele bovino alternativo, em substituição ao pó de pele comercial, para a determinação de tânicos em extrato vegetal oriundo da casca de acácia-negra (Acacia mearnsii De Wild.). A metodologia baseou-se em adaptações de normas técnicas nacionais e internacionais relacionadas ao assunto. Foram avaliadas duas condições do pó de pele (levemente cromado e não cromado), combinados a três tempos de contato deste com a solução analítica (10; 40; e 960 minutos). Testes qualitativos foram realizados para visualizar a eficiência da detanização através de reações colorimétricas. O tempo de contato de 10 minutos da solução analítica com o pó de pele mostrou-se suficiente, especialmente quando utilizado pó de pele levemente cromado, sendo a detanização confirmada pelas reações colorimétricas. O aumento do tempo de contato proporcionou o aumento da absorção de substâncias não tânicas e, devido a isso, é desaconselhável. Portanto, o uso do pó de pele alternativo mostrou-se eficiente na quantificação do extrato tânico em pó, podendo ser utilizado como substituto do pó de pele comercial, o qual trata-se de um insumo padronizado, de alto custo e de difícil obtenção.

Aplicación de la metodología seis sigmas para mejorar la calidad de la estimación de densidad básica de la madera en Acacia mearnsii

La estimación de la densidad básica de la madera se realiza mediante el método tradicional regido por la Norma Tappi T 258 om-94, o bien, por la norma chilena NCh 176/2, las cuales son métodos destructivos, que demandan extensos tiempos, altos gastos en mano de obra y gran utilización de material. Buscando métodos que permitan reducir esos inconvenientes se testeó la metodología Seis Sigmas, utilizando el método DMAMC (Definir, Medir, Analizar, Mejorar y Controlar), para mejorar este proceso, y estimar este parámetro en tiempos y costos más reducidos. Para esto se probó la espectroscopía NIR (Near Infrarred) calibrada para predecir la densidad de la madera en Acacia mearnsii, utilizando polvo de astillado en estado seco obtenido de tarugos. El uso de esta tecnología fue apoyado con modelos estadísticos de regresión multivariantes de mínimos cuadrados parciales (PLS, Partial Least Squares), y se generó un modelo de calibración y un modelo de validación para el instrumento. El objetivo de este estudio fue mejorar los tiempos del cálculo de densidad básica, parámetro físico importante para la obtención de información de la biomasa, que se emplea como un estimador del material leñoso de una especie y del rendimiento que alcanzará en el pulpaje, así como para determinar la facilidad con la que esta se puede trabajar. Los niveles de predicción del modelo PLS fueron sobre el 80%, por lo que se valida el uso de la espectroscopía NIR como herramienta para predecir la densidad básica. Además, se aprecia un aumento en los indicadores de calidad, el nivel sigma aumentó de 0,18 a 3, el Cp de 0,26 a 1.08, el Cpk de 0,23 a 1 y los defectos por millón disminuyeron en un 99.6%. Además, utilizando la espectroscopía NIR disminuyen los costos en comparación con el método tradicional.