Food security, sustainability of food production, and greenhouse gas (GHG) production of ruminant livestock are topics that generate scrutiny and debates worldwide. In a scenario of increasing human population and concerns with climate change, it is necessary to increase animal-derived food in sustainable operations. Grazing systems are crucial for ruminant production worldwide, and in the tropics, well-managed grasslands can provide sustainable intensification of this activity. In these regions, production often relies on grass monoculture managed extensively, a practice that commonly has led to the occurrence of degraded soils, limited animal productivity, and increased intensity of GHG emissions. Silvopastoralism is a practice that promotes several ecosystem services, showing potential to maintain soil quality while reducing the environmental impacts of ruminant production. These systems also have the potential to improve animal productive performance and reduce GHG emissions. The review was guided by a search in the Web of Science database using population terms and refined by document type (Article) and language (English OR Portuguese) following PRISMA protocol. Infographics were created using the Bibliometrix package in R software (version 4.3.2), and a specific topic on Tithonia diversifolia (Hemsl.) A. Gray was explored to demonstrate the importance of this forage resource for tropical silvopastoral systems and its potential contribution to food security. The T. diversifolia shrub is widely distributed in Latin America and tropical regions and presents several characteristics that make it a good option for silvopastoral systems. Focusing on the tropics, our objectives were to present one literature review addressing the role of grazing ruminant production towards the current climate change and food security challenges. Additionally, we aimed to explore the state of knowledge on silvopastoral systems and the use of T. diversifolia, presenting their potential to cope with this scenario of increased concerns with the sustainability of human activities.

The feasibility of unconventional feed for ruminants must be analyzed for appropriate use as sources of energy or protein that contribute to a sustainable production system addressing concerns about climate change, greenhouse gas emissions, and food security. The objective of this study was to evaluate the nutritive value of by-products including bean residue (BR), bean straw (BS), cassava bagasse (CB), corn straw (CS), orange bagasse (OB), peanut shell (PS), sugarcane bagasse (SB), soybean hull (SH), and sugarcane straw (SS). Chemical composition, in vitro degradability, and fermentative parameters were analyzed and subjected to multivariate and principal component analyses. Crude protein content was highly variable among by-products with BR and SH presenting the highest values (p < 0.001). These values did not differ between BR and SH, while the lowest values were observed in OB, PS, SB, SS, CS, and CB. Neutral detergent fiber content was higher in SB, PS, CS, and SS (p < 0.001), while greater in vitro degradability was found for CB, BR, OB, BS, and SH (p < 0.001). However, the in vitro gas production (p < 0.001) and total short-chain fatty acid concentration (p < 0.001) were higher in CB, BR, BS, and OB. Multivariate cluster analysis showed three distinct groups with the most degradable in group 1 followed by group 2. These results demonstrate that the by-products used in this study did not impair in vitro fermentation, and thus have the potential to be used in the diets of ruminants and to improve the sustainability of the livestock production sector.

Background: Tithonia diversifolia Helms (Gray), is a robust shrubby forage plant with high integral biomass yield (stem and leaves); susceptible to heliophany and conditioning of bromatological characteristics, nutritional value, and modification of the rumen environment is due to genetic variability between genotypes. Objective: To evaluate the macromolar quality of the biomass of introductions T. diversifolia Helms (Gray) established in two locations, and the nutritional value, gas production and in vitro rumen environment promoted by the whole plant biomass established in Ecuador. Methodology: The chemical composition of the full plant (PITD) was considered based on Dry Matter (DM), Organic Matter (OM), Mineral composition (MC), Crude Protein (CP), neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF). In vitro gas production was evaluated according to Ankom Technology, considering Tiffon 85 there (Cynodon dactylon) at control, quantified or ammoniacal nitrogen (N-NH3), short-chain fatty acids (SCFA) and pH. The experiment was developed in a completely randomized design in factorial arrangement with three repetitions for the variable chemical composition, and the in vitro digestibility of the date processed through a random complete block design with six repetitions, in the ruminal ambient and production SCFA was analyzed through a completely randomized block design with three repetitions. Results: There were variable responses in the DM content for the effect of interaction P <0.01, and higher mineral content in El Carmen, Ecuador for introduction 13.5, with respect to the rest of the cultivars in both locations. NDF was significantly expressed (p0.05). The gas production of the introductions, except for 1.2, was similar to that produced by the control (Tifton 85), however, in the degradability of the OM, net gas production (Net GP) of DM and OM, stood out. introduction 1.2 compared to the control (P<0.01) and the rest of the introductions. The net GP of NDF exceeded 1.2 (p<0.02) than the control, also quantitatively to produce Acetic and Propionic Fatty Acid. Implications: The introductions of T. diversifolia Helms Gray based on the results obtained preserve macromolar characteristics, gas production and SCVFA production (short chain volatile fatty acids) in contrasting ecosystems such as Valle del Cauca, Colombia and Manabi in Ecuador. Conclusions: The introductions of T. diversifolia Helms Gray, maintain a good protein composition, produce low methane contents, have high performance in the fermentation of organic matter and the cell wall, which suggests its future use as a complement to the ration in conditions in conditions Edaphoclimatic of the province of Manabi.

Tithonia diversifolia (Hemsl.) A. Gray has significant potential as a forage source in silvopastoral systems, particularly in tropical conditions. However, its intensity and frequency management differ from those commonly applied to grasses. This study aims to evaluate T. diversifolia under two harvest intensities (30 and 40 cm stubble height) and four harvest frequencies (21, 28, 35 and 42 days), aligning with Brazil's traditional tropical grass management practices. Biomass production and nutritive value of forage, as well as in vitro rumen fermentation parameters, were assessed. We observed that the tested harvest intensities have a limited impact on the biomass production and nutritional value of T. diversifolia. Despite the linear increase in biomass production, lower harvest frequencies (i.e., longer regrowth period) significantly affect nutritional value, impacting the products of ruminal fermentation, as indicated by the in vitro assay. The methane production per gram of degraded organic matter (OM) and the OM allocated for microbial biomass production are affected by the harvest frequencies. Additionally, we observed that rainfall and canopy height have a stronger correlation with biomass production than harvest frequencies controlled by days. We conclude that T. diversifolia is minimally affected by harvest intensities and, for Brazilian edaphoclimatic conditions, it can be harvested with higher frequencies than those suggested for other regions.