Impact of a tannin extract on digestibility and net flux of metabolites across splanchnic tissues of sheep

Alternatives to the Use of Antibiotics in Animal Production

There is a growing demand for livestock products and by-products due to an increase in the human population globally. Farmers utilize feed additives and antibiotics to enhance growth and alleviate diseases to meet this increasing demand for meat and meat products. Although antibiotic use as growth promoters (AGPs) in the livestock industry has brought about a positive increase in production, the industry has also been negatively affected by the development of bacteria resistant to antibiotics and the presence of chemical residues in meat and excreta. Due to this, concerns have risen as this poses a health risk. Resistant bacteria can be transmitted to humans by consuming meat from antibiotic-fed animals or environmental spread from animal wastes. Therefore, action is required to curb this issue because it is estimated that the annual losses in GDP and death toll globally could increase because of the continuous use of antibiotics in livestock production. Hence, this review aims to examine natural alternatives that have the potential to replace antibiotics for food safety, health, and environmental reasons. These could bring a satisfactory impact on nutrient absorption for growth together with health-stimulating virtues.

Divergence effects between dietary Acacia and Quebracho tannin extracts on nutrient utilization, performance, and methane emission of ruminants: A meta-analysis

Extracts of Acacia and Quebracho have been used as a feed additive in ruminant diets; the effects, however, have been varied. This study used a meta-analysis approach to evaluate the use of those extracts on nutrient utilization, performance, and methane production of ruminants. A database was developed from 37 published papers comprising 152 dietary treatments. The result showed that a higher concentration of tannins was associated with a decrease (p < 0.05) in nutrient intake and digestibility. An increasing tannin concentration was negatively correlated with ammonia, acetic acid, and the ratio of acetic to propionic acid. Methane production decreased (p < 0.01) with the increasing tannin concentration. Nitrogen (N) balance parameters were not affected by the tannin concentrations, but fecal N excretion increased (p < 0.01) as the tannin concentration increased. The relationships between the Acacia and Quebracho and the changes in organic matter intake, milk fat concentration, butyric acid, valeric acid, and methane production were significantly different. In conclusion, it is possible to use both condensed tannins (CT) extracts as a methane emission mitigation without impairing the ruminant performance. Furthermore, the Quebracho showed more pronounced to decrease ruminal protein degradation and lower methane emission than the Acacia.

The Utilisation of Tannin Extract as a Dietary Additive in Ruminant Nutrition: A Meta-Analysis

Simple Summary

Tannin has been extensively assessed for its potential and utilisation as a ruminant feed additive in recent years and is becoming important due to its beneficial effects on modulating ruminant performance and health and mitigating methane emissions. However, evidence concerning the effect of tannin in extracted forms on ruminants appears to be inconclusive on whether it can genuinely provide either beneficial or detrimental effects for ruminants. Moreover, the effects of various sources, types of tannin extract, or appropriate levels of supplementation on ruminants remain unclear. Therefore, there is a need for a systematic evaluation concerning the effects of tannin extract on rumen fermentation, digestibility, performance, methane emissions, and metabolism of ruminants.

Abstract

The objective of this meta-analysis was to elucidate whether there are general underlying effects of dietary tannin extract supplementation on rumen fermentation, digestibility, methane production, performance, as well as N utilisation in ruminants. A total of 70 papers comprised of 348 dietary treatments (from both in vivo and in situ studies) were included in the study. The database was then statistically analysed by the mixed model methodology, in which different experiments were considered as random effects and tannin-related factors were treated as fixed effects. The results revealed that an increased level of tannin extract inclusion in the diet lowered ruminant intake, digestibility, and production performance. Furthermore, the evidence also showed that an increased level of tannin extract decreased animal N utilisation where most of rumen by-pass protein was not absorbed well in the small intestine and directly excreted in the faeces. Due to the type of tannin extract, HT is more favourable to maintain nutrient intake, digestibility, and production performance and to mitigate methane production instead of CT, particularly when supplemented at low (<1%) to moderate (~3%) levels.

Insights for the Valorization of Biomass from Portuguese Invasive Acacia spp. in a Biorefinery Perspective

Acacia spp. are widespread all over the Portuguese territory, representing a threat to local biodiversity and to the productivity of the forest sector. The measures adopted in some countries for their eradication or to control their propagation are expensive, have been considered unfeasible from practical and economical perspectives, and have generated large amounts of residue that must be valorized in a sustainable way. This review brings together information on the valorization of bark, wood, leaves, flowers, pods, seeds, roots, and exudates from Acacia spp., through the production of high-value bioactive extracts (e.g., antioxidant, antimicrobial, anti-inflammatory, antidiabetic, antiviral, anthelmintic, or pesticidal agents, suitable to be explored by pharmaceutical, nutraceutical, cosmetics, and food and feed industries), its incorporation in innovative materials (e.g., polymers and composites, nanomaterials, low-cost adsorbents), as well as through the application of advanced thermochemical processes (e.g., flash pyrolysis) and pre-treatments to decompose biomass in its structural components, regarding the production of biofuels along with valuable chemicals derived from cellulose, hemicellulose, and lignin. The knowledge of this research is important to encourage an efficient and sustainable valorization of Acacia spp. within a biorefinery concept, which can bring a significant economic return from the valorization of these residues, simultaneously contributing to forest cleaning and management, to reduce the risk of fires, and to improve the social-economic development of rural areas.