Black Wattle Research Articles

Condensed tannins from black wattle as a promising nutritional additive for Nile tilapia: growth, immune and antioxidant responses, and gut morphology

The present study aimed to investigate the potential of condensed tannins (CT), derived from black wattle (Acacia mearnsii) tree bark, as a nutritional additive for Nile tilapia (Oreochromis niloticus) juveniles. CT are known for their antioxidant and immune-modulating properties, and their inclusion in aquafeeds may enhance fish health and performance. In this study, six diets were formulated: one control diet (Con) with no additives, and five experimental diets supplemented with CT extract at concentrations of 150, 250, 500, 750, and 1000mg/kg (CT150, CT250, CT500, CT750, CT1000, respectively). The selection of these doses was based on previous studies indicating that lower concentrations (below 1000mg/kg of diet) of tannins may offer benefits, while higher concentrations could exhibit antinutritional effects. After a 90-day feeding trial, fish fed the CT150 diet exhibited significantly higher growth compared to the control group. Additionally, fish in the CT150 group showed higher plasma lysozyme activity, while myeloperoxidase activity and hemolytic activity of the complement system were significantly higher in all tannin-fed groups compared to the control. Notably, CT150-fed fish demonstrated liver antioxidant responses comparable to or better than the control group, with no significant increase in lipid peroxidation, suggesting antioxidant protection. Histological analysis revealed a significant increase in intestinal villi density in the CT150 and CT500 groups compared to the control. While all groups showed an increase in absorption surface area (ASA), this increase was statistically significant only in the CT250, CT500, and CT750 groups when compared to the control. Furthermore, the CT150 diet led to the highest survival rate (80%) following a bacterial challenge. These findings suggest that dietary supplementation with 150mg/kg of CT from black wattle bark provides the most beneficial effects on growth, immune response, and survival in Nile tilapia juveniles.

Variation in soil water content and groundwater levels across three land cover types in a floodplain of the Kromme catchment, South Africa

AbstractInvasions of floodplains and riparian areas by alien woody species replacing predominantly herbaceous indigenous vegetation have altered the hydrological and ecosystem functioning in catchments. Although existing studies have examined changes in river flows following the establishment or clearing of alien woody vegetation, our understanding of impacts on soil water content and groundwater remains poor. Limited process knowledge restricts our capacity to reliably model and predict the impacts of land cover changes. As such, this work compared temporal variations in soil water content (SWC) and groundwater levels at three locations with different vegetation types: black wattle (Acacia mearnsii) trees, palmiet (Prionium serratum), and grass (dominated by Pennisetum clandestinum spp), within a floodplain site in the Kromme Catchment in the Eastern Cape Province of South Africa. Soil water content and shallow groundwater levels (< 4 m below ground) were monitored from August 2017 to December 2019 using soil moisture probes and piezometers. Rainfall, vegetation type and antecedent conditions were identified as the major factors controlling observed responses. On average, soil water content and water retention were significantly higher (p < 0.05) at the palmiet site, whilst the wattle site had the lowest SWC among the three sites. Shallow groundwater levels were also higher at the palmiet and grass sites and lowest at the wattle site. Results showed the negative impacts of black wattle trees on SWC and groundwater levels. These results are crucial for improved quantitative predictive capacity which would allow for better catchment management, for example, informing water supply planning and guiding restoration programs focusing on alien plant clearing.

Performance and intestinal health of piglets in the nursery phase subjected to diets with condensed black wattle (Acacia mearnsii) tannin.

The objective of this study was to evaluate the use of condensed tannin from black acacia (Acacia mearnsii) as a substitute additive for zinc oxide and growth-promoting antibiotics on the performance, digestibility, and intestinal health of piglets in the nursery phase. A total of 200 PIC® piglets that were 22 days old and weighed 6.0±0.9 kg were subjected to four treatments in the nursery phase (22 to 64 days of age): CONTR (control diet); ENR+ZnO (control diet + 10 mg/kg of enramycin + 2,500 mg/kg of zinc oxide during the first 21 days); BUT (control diet + 900 mg/kg of sodium butyrate) and TAN (control diet + 2,000 mg/kg of condensed tannin). The experimental design was a randomized block with 4 treatments and 10 replicates, with a pen of five animals each as the experimental unit. The zootechnical performance, diarrhea index score, dietary digestibility and metagenomics of the deep rectum microbiota were evaluated. The TAN had greater weight gain in the nursery phase and final weight (p<0.05) than the CONTR (394 vs. 360 g/d, and 22.6 vs. 21.1 kg, respectively), with these values being intermediate for the ENR+ZnO and BUT (365 and 382 g/d, and 21.3 and 22.1 kg, respectively). There was no difference between treatments for semi-liquid diarrhea (score 2), but CONTR had more cases of severe diarrhea (score 3; p<0.05) than ENR+ZnO, BUT and TAN, with 42, 18, 29 and 21 cases, respectively. The treatments had no impact on rare taxa or the relative abundances of taxonomic groups (uniformity), but the use of TAN promoted an increase in the abundances of Brevibacillus spp. and Enterococcus spp. compared to the other treatments (p<0.05). The use of condensed tannin from black wattle as a performance-enhancing additive was effective, with effects on performance and intestinal health, demonstrating its potential as a substitute for zinc oxide and enramycin in the diets of piglets in nursery phase.

Comparative ecotoxicological evaluation of tannin coagulants from black wattle and ferrous aluminum sulfate in the treatment of slaughterhouse effluent

Ecotoxicological assessments are crucial for environmental monitoring as they can pre-dict the adverse effects of ecotoxins, such as coagulants, on the ecosystems using contamination bioindicators. This study evaluated the ecotoxicity of two types of coagulants, an inorganic coagulant, ferrous aluminum sulfate (SF), and a biocoagulant based on tannins extracted from black wattle, used in the treatment of cattle slaughterhouse effluents. The planaria Girardia tigrina, which is used as a bioindicator of toxicity in freshwater ecosystems, was used as the test organism for this study. To select the appropriate tannin coagulant for the effluent under study, two types of biocoagulants were investigated: Tanfloc SG (SG) and Tanfloc MTH (MTH), with SG coagulant showing better performance (98.5 % turbidity removal). In the ecotoxicological test, SG and SF coagulants were compared. Both the tannin-based coagulant SG and the inorganic SF were effi-cient for the treatment of the evaluated effluent, yet their lethal concentrations (LC50 - 96h) with regard to G. tigrina was 32.24 % and 42.24 %, respectively. Thus, our results suggest that the effluent treated with the tannin-based coagulant SG showed greater toxicity to G. tigrina than the inorganic coagulant ferrous aluminum sulfate.

Exploring the Impact of Steam Explosion Pretreatment on the Binding Characteristics of Coal-Biomass Briquettes: A Study on Lignocellulose Type and Fibre Morphology

AbstractThe urgency to shift from coal to renewable energy sources drives the need for innovative solutions. Steam exploded lignocellulose acting as both binder and fuel in coal-briquetting presents a pathway for this transition whilst utilizing waste coal-fines. However, the applicability of different industrially relevant feedstocks and their specific binding mechanism is unknown. In this study we assess the impact of treatment severity and explosion pressure on fibre properties and briquette tensile compressive strength (TCS) across four feedstocks (sugarcane bagasse (SCB), corn stover (CS), black wattle (BW), and pine). Lignocellulose was steam exploded at severities ranging from 3.53 to 4.71 and physical modifications due to explosion pressure was isolated by conducting explosive decompressions at pressures ranging from 3 to 22.5 bar. Briquettes, prepared using 18% by mass steam exploded lignocellulose as a binder, were quantified for TCS and results showed that as particle aspect ratio increased, so did TCS, regardless of lignocellulose type. For SCB, CS, and BW, high explosion pressure and low to moderate severity (3.5–3.8) produced the highest aspect ratios and, consequently, highest TCS (1288, 1181, 905 kPa respectively). However, at high severity and pressure, a reduction in aspect ratio was observed and, subsequently, TCS. Pine required high severity and pressure to produce barely acceptable briquette TCS (364 kPa), due to its low aspect ratio. Physical modification of fibre aspect ratio during steam explosion therefore played a crucial role in its binding performance in coal-briquettes and the relative success of SCB, CS and BW indicate that there are significant resources of lignocellulose available for this technology and allow for widespread industrial application. Graphical Abstract

Changes in protein expression in Acacia mearnsii De Wild (black wattle) as a result of exposure to frost-inducing temperatures

Acacia mearnsii De Wild (black wattle) is one of the most important forestry crops in South Africa. The bark of this species contains high-quality tannins, while its wood is used for wood chips, charcoal and mining timber. One of the main problems faced by black wattle farmers is frost damage, thus there is an urgent need to develop frost-tolerant black wattle varieties. A quick method for the screening of frost tolerance variation would be beneficial for black wattle breeders and would result in the need for fewer families to undergo field trials. Frost tolerance in plants is directly related to their ability to undergo cold acclimation in response to changing weather conditions. During the cold acclimation process, many physiological changes occur, including modifications in protein expression. In this study, two-dimensional gel electrophoresis was used to investigate changes in protein expression among 40 black wattle families with varying levels of frost tolerance before and after a cold-stress treatment. The proteomic data generated from this was analysed using multivariate analysis. Six proteins were observed to be upregulated in frosttolerant black wattle families. The proteins were identified and have been previously shown to contribute to the protection of cellular membranes, maintenance of photosynthetic processes and the prevention of protein misfolding and aggregation.

Comparative Analysis of the Impacts of Commercial Exotic Forestry on Soil Fertility In the Southern Highlands of Tanzania: A Study of Pine, Eucalyptus and Black Wattle Plantations

Comparative Analysis of the Impacts of Commercial Exotic Forestry on Soil Fertility In the Southern Highlands of Tanzania: A Study of Pine, Eucalyptus and Black Wattle Plantations

Impact of exotic plantation on native Grassland Biodiversity: A 30-Year analysis in Tanzania’s southern highlands

Exotic trees have been introduced in various parts of the world for commercial and environmental reasons such as restoring degraded land and regulating the climate. Despite their economic benefits, they have been found to cause habitat loss and fragmentation, affect soil nutrient cycling, and deplete water quality and quantity. This study examined the extent of land use and land cover changes over the past 30 years, as well as the influence of exotic plant species on native grassland plant composition and diversity in Tanzania’s southern highlands. Drivers and the extent of changes were studied using Landsat imagery in 1990, 2000, 2010 and 2020. The study examined understory native plant species in 12 study sites, including grasslands as control sites near exotic plantations. The study used transects and rectangular plots to compare native plant species with those in exotic tree plantations. Trees with a stem diameter at breast height (DBH) of 10 cm or more were documented in 25 x 20 m plots, while shrubs with a DBH of 5 cm or more but less than 10 cm were recorded in 5 x 2 m sub-plots and grass as well as herbs were recorded in sub-sub plots of 2 x 0.5 m. The native plant composition and diversity were compared among exotic plantations (pine, eucalyptus and black wattle) and neighbouring grasslands. The generalised linear model (GLM) calculated the species abundance, while the native plant diversity in exotic plantations and grasslands was compared using a one-way analysis of variance (ANOVA). The study found that native species diversity is negatively impacted by exotic tree plantations, which displace natural grasslands (p < 0.05). Thus, wild medicinal plants, edible foods and habitats for flora and fauna, including pollinators, have decreased. The study recommends that afforestation and reforestation should emphasise native tree species for nature conservation.

Tannin Industry Waste-Derived Porous Carbon: An Effective Adsorbent from Black Wattle Bark for Organic Pollutant Removal

In Brazil, a significant part of the biomass is unused, contributing to environmental pollution. The tannin industry commonly extracts tannins from the bark of Acacia mearnsii or black wattle, leaving a significant residue of 70% (w w−1). This study investigates the conversion of black wattle bark into a porous carbonaceous material to efficiently remove organic pollutants. Using ZnCl2 as a chemical activation reagent, the experiments varied the impregnation time, carbonization rates, and temperatures. Additional experiments aimed to increase the specific surface area (SSA). X-ray diffraction (XRD) analysis showed the formation and removal of ZnO, which increased porosity. Scanning electron microscopy (SEM) showed an irregular morphology with pores. Fourier-transform infrared (FTIR) spectroscopy indicated characteristic bands, and electron paramagnetic resonance (EPR) detected organic free radicals. The SSAs exceeded 1000 m2 g−1, averaging 1360 m2 g−1, with a maximum of 1525 m2 g−1. Micropores (1.4 nm) were consistent. The structure of the material and the high SSA suggest a potential for efficient removal of aromatic impurities by π–π interactions. This approach addresses the issue of biomass waste, provides a solution for environmental remediation, and represents a transformative strategy for biomass utilization.

Seleção de Acacia mearnsii para a propagação por miniestaquia

ABSTRACT: Acacia mearnsii De Wild. (Black wattle) is a forest species with great social and economical importance for the southern region of Brazil. This species has multifunctional characteristics, being cultivated to produce tannin, cellulose and energy. This research identified black wattle genotypes with competence for adventitious rooting for mini-cutting propagation. Single-bud mini-cuttings were treated with IBA at a concentration of 2000 mg L-1. After 30 days of cultivation in a humid chamber, the mini-cuttings were evaluated for percentages of survival, rooting, number of roots, average length of the three largest roots, and the number of mini-cuttings rooted per mini-stump. The identification of the best genotypes was performed with the Selegen REML/BLUP software. Selection between and within black wattle progenies can be performed based on the number of rooted mini-cuttings, making it possible to select genotypes with high competence for adventitious rooting while maintaining genetic variability for new selection cycles to develop clones for vegetative propagation by mini-cutting.

Tanino condensado de acácia-negra (Acacia mearnsii) como aditivo nutricional em dietas de leitões desmamados

ABSTRACT: This study evaluated the effect of black wattle (Acacia mearnsii) condensed tannin extract in simple and complex diets for weaned piglets on performance, faecal consistency and serum haptoglobin concentrations. Eighty-eight female and castrated male piglets were used, weaned at 28 ± 3 days old, with an initial body weight of 8.02 ± 1.21 kg, housed in same-sex pairs and distributed in four treatments in a 2 x 2 factorial experiment in a randomised complete block design. The experimental treatments were simple diet (SD), simple diet + tannin (SD+T), complex diet (CD) and complex diet + tannin (CD+T). The simple diets contained lower concentrations of dairy ingredients, inclusion of barley and no addition of zinc oxide, palatant, acidifier and yeast. The diets with tannin were supplemented with 1,850 mg kg-1 of black wattle condensed tannin extract. The feed programme consisted of three diets: Pre-starter I (0-7 days), Pre-starter II (8-21 days) and Starter (22-28 days). Feed and water were available ad libitum. Body weight and feed intake were measured weekly to calculate the average daily feed intake, daily weight gain and feed conversion ratio. The faecal consistency score was measured daily to calculate the diarrhoea occurrence percentage. Blood samples for serum haptoglobin concentration were collected at 7 and 14 days after weaning. The addition of condensed tannin had no effect (P &gt; 0.05) on evaluated performance variables for weaned piglets. The diet type also did not affect the piglets’ performance (P &gt; 0.05). The inclusion of black wattle (Acacia mearnsii) condensed tannin does not affect piglet performance, reduces the incidence of diarrhoea in the first week after weaning and decreases the haptoglobin inflammatory response.

Electrical resistivity of heat-treated charcoal

The aim of this investigation was to determine the effect of high-temperature heat treatment on the electrical resistivity of charcoal. Samples of two different wood types (eucalyptus and black wattle) were pyrolised in a retort at a temperature of 700°C and the resulting charcoals heat-treated in an induction furnace at temperatures from 800°C to 1800°C and residence times from 60 to 120 minutes. After cooling, the resistivities of the samples were measured at room temperature using the four-point probe technique. It was found that as the heat treatment temperature increased the electrical resistivity of the charcoal decreased, approaching an asymptotic value at higher temperatures. Longer residence times decreased the resistivity, but this effect was not pronounced.

Soil nutrient dynamics, harvest residue management and soil organic matter conservation for the sustainability of black wattle production systems in subtropical soils: a review

Soil nutrient dynamics, harvest residue management and soil organic matter conservation for the sustainability of black wattle production systems in subtropical soils: a review

The use of condensed tannin in lambs' diet alters the rumen protozoa population without affecting growth performance

The aim of this study was to evaluate the effect of different doses of Black Wattle (Acacia mearnsii) condensed tannin on performance, dry matter intake, blood parameters, and identification and quantification of the rumen protozoa population at fasting and after feeding of feedlot lambs. Sixteen Santa Ines intact ram lambs and sixteen Santa Ines ewe lambs were distributed and randomly assigned to 1 of 4 dietary treatments with different doses of condensed tannin (0 %, 1 %, 2 %, and 3 %) in the concentrate, on a feedlot system. No significant treatment effect (P > 0.05) was observed for growth performance, dry matter intake, and blood parameters. No significant effects of treatment (P > 0.05), phase (fasting and after feeding) (P > 0.05), and interaction between treatment and phase (P > 0.05) were observed for total and differential protozoa percentage. However, differences were observed for total and differential protozoa count. A quadratic effect (P = 0.03) was observed for total counts of Diplodiniinae in the rumen fluid of animals fed 3 % of condensed tannin. A phase effect was observed for counts of Isotricha spp, Entodinium spp. Diplodiniinae, and total protozoa count with higher numbers observed at fasting when compared to after feeding. Results of this research suggest that up to 3 % of black wattle condensed tannin in the diet of lambs does not affect dry matter intake, animal performance, and blood parameters.

Obtaining of a rich-cellulose material from black wattle (Acacia mearnsii De Wild.) bark residues.

Black wattle (Acacia mearnsii De Wild.) barksare residues produced by tannin industries in huge quantities, which are normally discharged on environmental or used for energy production. Therefore, this study aimed to evaluate the use of black wattle bark residues as a raw material on obtaining of a rich-cellulose material by alkaline (MET1), acetosolv (MET2), and organosolv (MET3) procedures. The results obtained indicated that the alkaline methodology, followed by a bleaching step (MET1), promoted klason lignin and hemicellulose removals more efficiently. It was possible to observe that better results were achieved using NaOH concentration of 6% (wt%), at 65 °C for 2.5 h, presenting a yield of 63.24 ± 1.25%, and a reduction on klason lignin content of almost 90.45%. Regarding the bleaching step, it was possible to obtain a material free of non-cellulosic compounds with a yield of 78.28 ± 1.48%. Thermogravimetric analysis indicated the removal of lignin and hemicellulose as well as an increase in cellulose degradation temperature, due to changes in crystalline phases. According toX-ray diffraction (XRD), the procedures employed have led to an increase in crystallinity from 66.27 to 91.78% due to the removal of non-cellulosic compounds. Scanning electron microscopy (SEM) showed morphological alterations in accordance with the removal of non-cellulosic compounds.

Enhanced degradation of methionine by eco-friendly and low-cost tannin extract modified Fenton oxidation: Promotion of the Fe(III)/Fe(II) cycle

In this study, a low-cost natural biomass extracted from higher plants - Tannin - was used to improve the Fenton system by promoting iron cycling due to the abundant phenolic hydroxyl groups in the molecular structure. Tannin extract (TE) of black wattle was combined with Fe(Ⅱ)/H2O2 system at room temperature and under pH 3 to 8. Methionine (Met) was chosen as a target pollutant, as its critical role in the global sulfur cycle and algae-induced black bloom events. The results found that TE could significantly promote Fe(Ⅱ)/H2O2 system, Met degradation increased from 44 % to 86 % under pH 6.0, and the mineralization increased from 14.86 % to 38.96 %. Both quenching experiments and electron paramagnetic resonance (EPR) analysis confirmed that OH and O2− contributed to Met degradation, and OH played a key role in TE/Fe(Ⅱ)/H2O2 system. The reducibility of TE at different pH values was evaluated, the highest Fe(Ⅲ) reducing rate of TE was obtained at pH of 4.5 (k = 22.48 M−1min−1) based on the formation model. TE and its complex catalyzed the dismutation of O2− to form OH. The degradation rate constant of TE/Fe(Ⅱ)/H2O2 system was 3.63 min−1, and the intermediates of Met degradation was proved to be non-toxic. In conclusion, TE could facilitate the iron recycle in Fenton system, consequently to strengthen H2O2 activation, and it offered an energy-saving and eco-friendly way for organic pollutants treatment.

Indole acetic-producing bacteria promote the root development of Acacia mearnsii cuttings

ABSTRACT Black wattle (Acacia mearnsii) is one of the most important commercial tree species in southern Brazil, where it is planted for multiple uses, such as cellulose pulp production and tannin extraction. Recently, forest companies have been directing their efforts towards vegetative propagation to improve the productivity of black-wattle plantations. However, rooting rates of this species are low, even when treated with the synthetic auxin indole-3-butyric acid (IBA). Thus, rooting black-wattle cuttings is still considered a bottleneck for industry development. On the other hand, it is known that inoculating cuttings with indole acetic acid (IAA)-producing bacteria can be an efficient method for increasing vegetative propagation. This study investigated the potential of two bacterial strains to promote root development in black wattle. The strains SEMIA 436 and 439 (Agrobacterium radiobacter), previously isolated from the common bean and detected as high-IAA producers, were also evaluated in relation to their colonisation capacity in seedling roots. Results showed that inoculation with both strains increased rooting rates by 20−30% compared with non-treated and IBA-treated cuttings. Moreover, inoculation increased root dry mass, length and volume. Strain SEMIA 436 demonstrated higher colonisation capacity.

First report of the wattle rust pathogen, Uromycladium acaciae (Raveneliaceae, Pucciniales) in Ethiopia

Abstract Australian Acacia species are among the most important trees planted for wood and pulp production in several African countries, including Ethiopia. In 2020, symptoms of a serious shoot and leaf rust disease were observed on black wattle (Acacia mearnsii De Wild.) trees across the three main wattle growing regions of Ethiopia. The aim of this study was to describe the disease and identify its causal agent based on morphological characteristics as well as DNA sequence data for the ITS and LSU regions of ribosomal DNA. Here we report for the first time, the presence of the wattle rust pathogen, Uromycladium acaciae, in Ethiopia.

Source of Tannin from black wattle

Source of Tannin from black wattle

Determination of productivity, rooting and nutrient profile of Acacia mearnsii (black wattle) hedge plants

ABSTRACT The poor rooting of black wattle, Acacia mearnsii, has previously limited its commercial propagation, but research at the Institute of Commercial Forestry has enabled many commercial nurseries in South Africa to supply the industry with rooted cuttings. This paper provides an understanding of the management of A. mearnsii potted hedge plants with regards to productivity, rooting ability and profiling foliar nutrients. Hedge plants in two bag sizes (5 l and 40 l) of differing ages (8 months and 24 months) were investigated. No significant differences were noted in rooting between bag sizes. However, when coupled with productivity data, the 40 l hedge plants generated higher numbers of predicted rooted cuttings. Although the productivity in both bags increased over time, rooting ability declined, possibly because of observed increases in N and S and decreases in P, Mg, Fe, Zn and B, all of which are important for root growth and development. Productivity results indicate that hedges can be kept for at least 53 months before needing replacement. Rooting results showed no decrease in productivity or rooting from cascaded hedge plants. Results from the nutrient profiling of foliar data provide a unique benchmark for nurseries to successfully manage their hedge plants.