Feed Additive Research Articles

Influence of lemongrass and oregano essential oils and their combination on in vitro ruminal fermentation and greenhouse gas emissions in total mixed ration for dairy cows

Ruminants play a crucial role in the food chain, but are also considered contributors of greenhouse gas (GHG) emissions . Essential oils (EOs) are emerging as natural feed additives in ruminants’ nutrition to enhance animal health, performance and reduce environmental footprint. Among EOs, lemongrass (Cymbopogon winterianus) and oregano (Origanum vulgare) EOs (LEO and OEO) have attracted attention as modulators of ruminal fermentations, but their role needs to be clarified. The experiment was designed using a randomised setup to assess the effects of LEO and OEO on in vitro ruminal fermentation and GHGs, using total mixed ration (TMR) as substrate (incubation time 24h). Experimental treatments included (doses as % of TMR on DM basis): 1) control only TMR (0% EOs) 2) 0.07% LEO 3) 0.07% OEO 4) 0.035% LEO + 0.035% OEO 5) 0.07% LEO + 0.07% OEO. Each treatment was repeated three times in two experimental runs. Only EO combinations reduced total gas (−9%, p=0.001). All EOs decreased CO2 emissions by −5 to −12% with no significant differences between treatments (p<0.001), although anti-methanogenic effects were not observed (p=0.192). Volatile fatty acids were slightly affected only by EOs blend at the highest dose, resulting in a reduction of propionate (−1.3%, p=0.02), an increase in acetate:propionate (+0.16%, p=0.04) and isovalerate (+0.7%, p=0.03). LEO reduced pH (−0.6%, p=0.004), while OEO increased oxidation capacity (+4.2%, p=0.004), but both parameters remained within physiological ranges. Canonical discriminant analysis confirmed distinct EOs effects, highlighting their potential as natural additives for improving ruminal fermentation and mitigating ruminant environmental footprint.

Enhancing growing rabbit heat stress resilience through dietary supplementation with natural antioxidants

Animal husbandry development is influenced by various factors, with heat stress (HS) being a significant factor. The aim of this experiment was to explore the potential of natural antioxidants such as vitamin C (VITC), vitamin E (VITE), lycopene (LYC), and allicin (AL) in enhancing growth, immune function and maintaining the redox status of fattening rabbits under HS. Male weaning rabbits (n = 150, 5 weeks of age) were randomly assigned to 5 groups. The rabbits were fed a basal diet (control group) or supplemented with 40 mg of vitamin E (VE40), 5 mg of vitamin C (VC5), 150 mg of lycopene (LYC150), or 150 mg of allicin (AL150) per kg of diet, respectively, under summer Egyptian conditions. The overall temperature humidity index (THI) value was 29.76, indicating severe HS during the experimental period. The findings indicated that all dietary supplemented groups showed significant improvements in live body weight at 8 weeks (P < 0.0001) and 11 weeks (P < 0.05) of age compared to the control group. The feed conversion ratio (FCR) was improved with all additives (P < 0.05), while feed intake and carcass traits were not affected by the treatments (P > 0.05). The AL group had the highest dressing percentage compared to the other groups (P < 0.05). Feeding stressed rabbits with antioxidant supplements resulted in a higher hemoglobin concentration compared to the control group (P < 0.05). Aspartate transaminase (AST), triglycerides, and creatinine levels were decreased with all additives as compared to the control group (P < 0.05). Total protein and albumin were significantly higher in AL group than in other groups (P < 0.05). The serum Immunoglobulin G (IgG) was significantly increased, while tumor necrosis factor alpha (TNF-α), interleukin-4 (IL-4), and interferon gamma (IFN-γ) were decreased by all feed additives (P < 0.05). Immunoglobulins (IgA and IgM) did not differ among all experimental groups (P > 0.05). Serum total antioxidant capacity (TAC) and glutathione (GSH) levels were higher in all supplement groups compared to the HS group (P < 0.05). All dietary supplements significantly reduced malondialdehyde (MDA) levels in liver tissues and blood serum compared to the control group (P < 0.05). Collectively, allicin emerged as a potent shield against heat stress, bettering lycopene and vitamins E and C in safeguarding the well-being of growing rabbits.

Application of Natural Antioxidants as Feed Additives in Aquaculture: A Review.

Oxidative stress, a critical factor affecting the health and productivity of aquatic organisms, arises from the imbalance between reactive oxygen species (ROS) production and antioxidant defenses. In aquaculture, natural antioxidants have gained increasing attention as sustainable feed additives to mitigate oxidative damage, enhance immune responses, and improve overall growth performance. This review provides a comprehensive synthesis of the antioxidative mechanisms of key natural antioxidants, including carotenoids, polysaccharides, vitamins, polyphenols, and flavonoids. By neutralizing ROS and modulating cellular signaling pathways such as Nrf2/ARE, these compounds offer significant protective effects against oxidative damage in aquatic species. The manuscript consolidates recent advancements in antioxidant research, highlighting their practical applications in feed formulation and their role in promoting sustainability in aquaculture. This review aims to provide an integrative framework for understanding natural antioxidants' potential, guiding future research and practical implementation in aquaculture systems.

Lactobacillus acidophilus alleviate Salmonella enterica Serovar Typhimurium-induced murine inflammatory/oxidative responses via the p62-Keap1-Nrf2 signaling pathway and cecal microbiota

BackgroundSalmonella enterica Serovar Typhimurium (S. Typhimurium) infection can cause inflammation and oxidative stress in the body, leading to gastroenteritis, fever and other diseases in humans and animals. More and more studies have emphasized the broad prospects of probiotics in improving inflammation and oxidative stress, but the ability and mechanism of Lactobacillus acidophilus (LA) to alleviate the inflammatory/oxidative reaction caused by pathogens are still unclear.Methods and resultsIn this study, we treated the mice with LA for 14 days, infected them with S. Typhimurium for 24 h, and sacrificed the mice to collect samples. We found that the early intervention of LA alleviated the pathological injury and reversed the down-regulation of the duodenal and hepatic tight junction protein mRNA levels caused by S. Typhimurium infection. Compared with S. Typhimurium group, LA early intervention increased the expression of antioxidant enzymes, but decreased the levels of serum malondialdehyde (MDA), interleukin-8 and tumor necrosis factor-α (TNF-α). Additionally, LA early intervention significantly increased Nrf2 mRNA expression in the liver and decreased Keap1 mRNA expression in the duodenum compared to the S. Typhimurium group. Furthermore, early LA treatment reduced the abundance of Bacteroides acidificiens, increased the abundance of Akkermansia, and alleviated the decrease in SCFAs levels in the cecum of S. Typhimurium-infected mice. Spearman correlation analysis showed that there was a certain correlation between cecal flora and serum indicators and short chain fatty acids.ConclusionTaken together, the results indicate that LA early intervention may alleviates S. Typhimurium-induced inflammation and oxidative responses in mice by activating the p62-Keap1-Nrf2 signaling pathway and regulating the gut microbial community.Significance and impact of the studyExploring the ability of LA to resist animal oxidative stress and microflora regulation caused by pathogenic microbes, so as to provide more options for developing healthy disease-resistant feed additives.

N-acetyl-L-cysteine and lauric acid; effective antioxidant and antimicrobial feed additives for juvenile Pacific white shrimp (Litopenaeus vannamei) cultured at high stocking density.

Present study aimed at improving the immune and antioxidant response of Pacific white shrimp (Litopenaeus vannamei) cultured at high stocking density fed with 0.2% supplementation of lauric acid (LA) and N-acetyl-L-cysteine (NAC). Shrimp (initial average weight = 0.65 g; n = 270) were grown at low stocking density (LSD) (n = 10/0.80 ft3 per replicate) and high stocking density (HSD) (n = 20/0.80 ft3 per replicate). They were randomly distributed into five groups (T1: negative control at LSD, T2: positive control at HSD, T3: at HSD and fed with LA supplement diet, T4: at HSD and fed with NAC supplemented diet, T5: at HSD and fed with combination of LA and NAC). All these five treatments were studied in triplicates and study continued for eight weeks. Better growth and higher levels of glucose, total protein, total hemocyte count and phagocytic index were observed in shrimp fed with NAC and LA supplemented diets. Observed survival rate and feed conversion ratio in all treatments was 75-89% and < 0.82, respectively. All parameters indicating stress were observed to be higher in T1 as compared to T2. Improved expression of superoxide dismutase and glutathione peroxidase and lower levels of malondialdehyde genes in T3, T4 and T5 showed that supplementation with these nutraceuticals can improve antioxidant response at high stocking density. A parallel increase was observed in the profiles of prophenoloxidase and lysozyme, underscoring the immune-boosting effects of both NAC and LA. This finding was further supported by higher expression of innate immune signaling pathway-related gene, toll like receptor-2 in T3, T4 and T5. In conclusion, NAC and LA, can possibly improve the resistance of white pacific shrimp against oxidative stress and pathogens when cultured in intensive production system.

Aquatic Invertebrate Antimicrobial Peptides in the Fight Against Aquaculture Pathogens.

The intensification of aquaculture has escalated disease outbreaks and overuse of antibiotics, driving the global antimicrobial resistance (AMR) crisis. Antimicrobial peptides (AMPs) provide a promising alternative due to their rapid, broad-spectrum activity, low AMR risk, and additional bioactivities, including immunomodulatory, anticancer, and antifouling properties. AMPs derived from aquatic invertebrates, particularly marine-derived, are well-suited for aquaculture, offering enhanced stability in high-salinity environments. This study compiles and analyzes data from AMP databases and over 200 scientific sources, identifying approximately 350 AMPs derived from aquatic invertebrates, mostly cationic and α-helical, across 65 protein families. While in vitro assays highlight their potential, limited in vivo studies hinder practical application. These AMPs could serve as feed additives, therapeutic agents, or in genetic engineering approaches like CRISPR/Cas9-mediated transgenesis to enhance resilience of farmed species. Despite challenges such as stability, ecological impacts, and regulatory hurdles, advancements in peptidomimetics and genetic engineering hold significant promise. Future research should emphasize refining AMP enhancement techniques, expanding their diversity and bioactivity profiles, and prioritizing comprehensive in vivo evaluations. Harnessing the potential of AMPs represents a significant step forward on the path to aquaculture sustainability, reducing antibiotic dependency, and combating AMR, ultimately safeguarding public health and ecosystem resilience.

Effects of Feed Supplementation With Fulvic Acid on the Systemic and Mucosal Protective Mechanisms of Juvenile Rainbow Trout (Oncorhynchus mykiss).

Rainbow trout (Oncorhynchus mykiss) is an important fish species raised in aquaculture, but it is susceptible to stress, infections diseases. The present study aimed to determine the effects of fulvic acid feed addition on the systemic and mucosal protective mechanisms of juvenile rainbow trout and to elucidate the underlying molecular mechanisms of changes in the gut. Rainbow trout (4.30 ± 0.6 g) diet was supplemented with different levels of fulvic acid: 0% (Control), 0.5%, 1% and 2%. At the end of 8-week feeding trial, growth parameters such as final weight gained weight (%), SGR (F1%) increased, and FCR (all levels) decreased significantly compared to the control group. We found that the activity of lysozyme, glutathione peroxidase, and catalase in the serum were significantly improved, especially after the addition of 0.5% and 1% of fulvic acid. At the same time, the immunoglobulin concentration in the skin mucus was increased with 0.5% supplementation. However, the expression of tnf-α, il-6 and gpx in the intestine was strongly upregulated after supplementation with 2%, indicating oxidative stress and inflammation with this level of fulvic acid inclusion. Furthermore, the mucus lysozyme activity was reduced at this concentration, which can increase the susceptibility to pathogen invasion. The results suggest that adding 0.5%-1% of fulvic acid to the feed of juvenile rainbow trout can help to improve their immune and antioxidative defenses and thereby support the wellbeing of fish.

Low-Concentration Hypochlorous Acid Drinking Water Alleviates Broiler Gut Microbial Load While Preserving Overall Growth Performance.

Hypochlorous acid has been attempted as an additive to animal drinking water in practical animal farming processes for water microbial quality control. Despite its potential, there is still a knowledge gap concerning the effects of hypochlorous acid on both poultry growth performance and gut microbial load. To address this gap, an animal study was conducted using flow cytometry to quantify the age-related microbial load in broiler manure and gut contents. We observed that the effect on growth performance was sustained only during the starter phase, with no significant impact throughout the entire production cycle. The treatment could reduce the microbial load of both fresh broiler manure and cecal contents. Despite this convergence in the duodenum, significant differences in microbial loads between the control and treatment groups persisted in the manure and cecal contents throughout the later stages. Our findings demonstrate that consuming low-concentration hypochlorous acid water over the long term can lower the microbial load in the broiler gut throughout the entire growth cycle without impacting overall growth performance. Future research on drinking or feed additives should incorporate microbial absolute quantification methods to achieve a more precise assessment of microbiota.

Journal Review: Effectiveness of Supplementary Feed Ingredients on Egg Productivity and Body Weight Gain of Balibangtan Superior Hens

Feed is a major determining factor in the success of layer and broiler farming. The nutritional content of the feed must meet the requirements to increase livestock productivity. To improve chicken performance, we use additional feed. This review aims to determine the effectiveness of feed ingredients as a feed supplementation for chickens by using production waste, forage, household waste, forage, and enzymes to increase the growth and production of KUB chickens. Ingredients that can be used as feed additives include coconut pulp, pumpkin waste flour, papaya leaf waste, teak leaf extract, moringa leaves, tilapia plants, betel leaf juice, BS4, selenium chitosan, phytase, xylooligosaccharide, kesum leaf flour, sago pulp, spinach waste, and BSF maggot. The results of this review showed that the most effective feed ingredient was the supplementation of teak leaf extract (Tectona grandis), with a protein content of 4.9%, being the most effective feed ingredient in increasing egg productivity up to 15%. The supplementation of kesum leaf flour, with an average body weight gain of 426.97 g/head, is the most effective feed ingredient for increasing body weight growth in KUB chickens.

Use of Feed Additives with Sorption Properties in Fish Farming: Literature Review

Use of Feed Additives with Sorption Properties in Fish Farming: Literature Review

A Review of Producer Adoption in the U.S. Beef Industry with Application to Enteric Methane Emission Mitigation Strategies.

Cattle are ruminant animals that produce enteric methane (CH4) emissions as a byproduct of their natural digestive process. U.S. beef producers have been receiving pressure to reduce production emissions. The scientific community continues to research and develop methods to reduce enteric methane emissions, but adoption of such strategies by U.S. beef producers remains unknown. We complete a review on producer adoption in the U.S. beef industry to shed light on potential factors that may impact the adoption of emissions-mitigating strategies by U.S. beef producers. After querying nine research databases, fifty-five studies were gathered and synthesized. These studies span the beef supply chain and focus on topics including feed additives, management practices, and reproductive technologies. Economic returns are a key driver of U.S. beef producer adoption decisions, with accompanying considerations for the impacts on consumer perceptions and demand. Segmentation in the U.S. beef supply chain, with animals typically changing ownership multiple times prior to slaughter, may result in challenges in tracing and verifying the adoption of climate-focused strategies. Targeting large-scale producers may be the most efficient avenue to achieving emissions reduction goals via the adoption of methane-mitigating strategies. Younger producers could additionally be a target demographic for adoption efforts.

Effects of Different Levels of Lycium barbarum Flavonoids on Growth Performance, Immunity, Intestinal Barrier and Antioxidant Capacity of Meat Ducks.

Background: In vitro findings on the biological functions of Lycium barbarum flavonoids (LBFs) as feed additives are limited. This study aimed to explore the effects of different concentrations of LBFs on the growth performance, immune function, intestinal barrier, and antioxidant capacity of meat ducks. A total of 240 one-day-old male meat ducks were randomly allocated to four groups, each receiving a basal diet supplemented with 0 (control), 250, 500, or 1000 mg/kg of LBFs for 42 d. Results: The results showed that dietary supplementation with 500 mg/kg of LBFs resulted in a significant increase in average daily feed intake, body weight, average daily gain, and feed conversion ratio. Dietary supplementation with 500 or 1000 mg/kg of LBFs resulted in significant decreases in serum levels of D-lactic acid and lipopolysaccharide. Dietary supplementation with 500 mg/kg LBFs significantly decreased diamine oxidase activity and enhanced the activities of catalase, total antioxidant capacity, and glutathione peroxidase in the jejunal mucosa, as well as the activity of total superoxide dismutase and the content of glutathione in the ileal mucosa, while significantly lowering the content of malondialdehyde in the ileal mucosa. Dietary supplementation with 500 mg/kg LBFs significantly up-regulated the mRNA expression of genes associated with intestinal barrier function and antioxidant capacity in the jejunal and ileal mucosa, as well as the protein expression of these antioxidant genes, and led to a significant reduction in the mRNA expression of pro-apoptotic and inflammatory-related genes. Conclusions: The addition of LBFs to the diet improved the growth performance, intestinal barrier function, immune response, and antioxidant capacity of the ducks, which may be closely associated with the activation of the Nrf2 signaling pathway and the inhibition of the NF-κB signaling pathway. The optimal dietary inclusion level of LBFs in ducks was 500 mg/kg.

Effects of Monensin, Calcareous Algae, and Essential Oils on Performance, Carcass Traits, and Methane Emissions Across Different Breeds of Feedlot-Finished Beef Cattle

With the growing use of crossbred cattle in Brazilian feedlots and increasing pressure to reduce antibiotic use as growth promoters, this study examines the impact of three feed additives—monensin (MON), monensin with Lithothamnium calcareum (LCM), and a blend of essential oils (BEO)—on the performance of Nellore (NEL) and crossbred (CROSS) cattle. A total of 90 Nellore and 90 crossbred bulls were assigned to a completely randomized block design with a 2 × 3 factorial design for 112 days, and all received the same diet with varying additives. Their methane (CH4) emissions were estimated. All data were analyzed using the emmeans package of R software (version 4.4.1). Crossbred cattle outperformed Nellore in average daily gain (ADG), hot carcass weight (HCW), and dry matter intake (DMI), though feed efficiency remained unaffected. Across additives, no significant differences were observed in ADG, HCW, or dressing percentage. However, LCM had a lower DMI than the BEO, while MON showed better feed efficiency than the BEO. A breed-by-additive interaction trend was noted for DMI as a percentage of body weight (DMI%BW), with Nellore bulls on LCM diets showing the lowest DMI%BW. Crossbreeds had greater net energy (NE) requirements for maintenance (NEm) and gain (NEg), and MON-fed animals had greater NEm and NEg than the BEO. Crossbred bulls had greater daily methane (CH4) emissions than Nellore bulls. Animals on the BEO had greater daily CH4 emissions and greater g CH4/kg metabolic BW than LCM bulls. In conclusion, the addition of Lithothamnium calcareum to monensin did not enhance performance compared to monensin alone. Monensin outperformed the BEO in feed efficiency and nutrient utilization.

Feed additives for methane mitigation: Assessment of feed additives as a strategy to mitigate enteric methane from ruminants-Accounting; How to quantify the mitigating potential of using antimethanogenic feed additives.

Recent advances in our understanding of methanogenesis have led to the development of antimethanogenic feed additives (AMFA) that can reduce enteric methane (CH4) emissions to varying extents, via direct targeting of methanogens, alternative electron acceptors, or altering the rumen environment. Here we examine current and new approaches used for the accounting (i.e., quantification) of enteric CH4 abatement by the use of AMFA in the livestock sector from the individual animal to the global scale. Along with this process, recommendations are provided on how to account for the mitigation potential at the animal level, as well as in farm-scale models, emissions trading schemes, life cycle assessment, and carbon (C) footprinting tools, and in regional and national inventories. In addition, an assessment of uncertainties and potential trade-offs and off-setting with the use of AMFA (i.e., efficacy vs. effectiveness, upstream and downstream emissions) is provided. The accounting of on-farm enteric CH4 emissions and benefits from the use of AMFA starts with the ruminant animal (with estimates obtained from a range of approaches, from simple empirical emission factors or equations to complex process-based models) and goes all the way to national and supranational accounting. The choice of methodologies and levels of complexity to account for mitigation of enteric CH4 (or total GHG) emissions in livestock systems must be tailored to the scale of analysis aimed, the availability of input data to represent contextualized conditions, and the accounting objectives (e.g., academic exercise vs. producer's GHG certification vs. national GHG inventory). The accounting of enteric CH4 mitigating effects needs to consider the AMFA delivery methods and synergies and trade-offs of GHG emissions at levels before and beyond (upstream and downstream) the animal to fully assess the impact of AMFA use. At large, the accounting of methane abatement by feed additives remains to be fully assessed beyond experimental results (efficacy) to address pragmatism (effectiveness), potential for adoption, and societal acceptance.

Feed additives for methane mitigation: Regulatory frameworks and scientific evidence requirements for the authorization of feed additives to mitigate ruminant methane emissions.

This article describes the regulatory and evidence requirements necessary for the authorization of antimethanogenic feed additives (AMFA) aimed at mitigating enteric methane (CH4) emissions from ruminants. It outlines the legislation and legal procedures in Australia, Canada, the European Union, New Zealand, South Korea, the United Kingdom, and the United States as illustrative examples, offering insights for applicants seeking authorization. Additionals objectives are to highlight consequential similarities and differences in regulations and evidence requirements and offer recommendations for scientists and applicants. The pivotal role that scientific evidence plays in the evaluation and approval processes is emphasized, along with the need for applicants and researchers to understand and adhere to the specific regulations of each jurisdiction. Feed additives are regulated to ensure their safety for animals, humans, and the environment, and to verify their effectiveness for the intended use of enteric CH4 mitigation. Regulations cover various aspects, including ingredient safety, manufacturing practices, product labeling, and the establishment of permissible limits for certain substances to ensure their safe use in animal feed. Compliance with these regulations is mandatory, and they are enforced by regulatory agencies within each jurisdiction, aiming to protect animal health, promote food safety, and prevent misleading claims and unsafe practices. The assessment processes involve evaluating scientific evidence submitted by applicants, along with evaluations of quality control procedures, and record-keeping practices. The major difference in regulations is that each jurisdiction developed unique criteria to legally classify AMFA, making it challenging to satisfy all legal classifications with a single set of criteria for scientific evidence. However, numerous similarities and a universal reliance on the concept of intended use indicate consistency across all jurisdictions on the need for robust evidence for efficacy, safety, and product quality and documentation even if the type, size, duration, and location of the studies they require differ. Recommendations are made for both scientists and applicants, emphasizing the importance of designing, conducting, and reporting scientific evaluations transparently, using validated standards and methods, and communicating with regulatory bodies to ensure compliance with regulations and evidence requirements.

Feed additives for methane mitigation: Recommendations for testing enteric methane-mitigating feed additives in ruminant studies.

There is a need for rigorous and scientifically-based testing standards for existing and new enteric methane mitigation technologies, including antimethanogenic feed additives (AMFA). The current review provides guidelines for conducting and analyzing data from experiments with ruminants intended to test the antimethanogenic and production effects of feed additives. Recommendations include study design and statistical analysis of the data, dietary effects, associative effect of AMFA with other mitigation strategies, appropriate methods for measuring methane emissions, production and physiological responses to AMFA, and their effects on animal health and product quality. Animal experiments should be planned based on clear hypotheses, and experimental designs must be chosen to best answer the scientific questions asked, with pre-experimental power analysis and robust post-experimental statistical analyses being important requisites. Long-term studies for evaluating AMFA are currently lacking and are highly needed. Experimental conditions should be representative of the production system of interest, so results and conclusions are applicable and practical. Methane-mitigating effects of AMFA may be combined with other mitigation strategies to explore additivity and synergism, as well as trade-offs, including relevant manure emissions, and these need to be studied in appropriately designed experiments. Methane emissions can be successfully measured, and efficacy of AMFA determined, using respiration chambers, the sulfur hexafluoride method, and the GreenFeed system. Other techniques, such as hood and face masks, can also be used in short-term studies, ensuring they do not significantly affect feed intake, feeding behavior, and animal production. For the success of an AMFA, it is critically important that representative animal production data are collected, analyzed, and reported. In addition, evaluating the effects of AMFA on nutrient digestibility, animal physiology, animal health and reproduction, product quality, and how AMFA interact with nutrient composition of the diet is necessary and should be conducted at various stages of the evaluation process. The authors emphasize that enteric methane mitigation claims should not be made until the efficacy of AMFA is confirmed in animal studies designed and conducted considering the guidelines provided herein.

Safety and efficacy of a feed additive consisting of chromium propionate (KemTRACE™ chromium) for all growing poultry species (KEMIN EUROPA N.V).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of chromium propionate as zootechnical feed additive for all growing poultry species. The safety and efficacy of chromium propionate has been assessed previously in 2021 by the Panel and it was concluded that the additive is considered safe for chickens for fattening and chickens reared for laying/breeding at the proposed use level 0.2-0.4 mg Cr/kg complete feed, but the conclusion was not extrapolated to other growing species. During that assessment, the EU Reference Laboratory for feed additives (EURL) was not in a position to recommend the method for official control for the quantification of the organic chromium content in premixtures and feedingstuffs. The applicant subsequently proposed a new method of analyses, incorporating a tracer in the composition of a premixture, which has been evaluated by EURL and recommended as official method for the quantification of the organic chromium content in premixtures and feedingstuffs. The safety of the use of the microtracer has been assessed in 2024. The Panel considered that the use of the microtracer as proposed in the conditions of use would not introduce safety concerns for the target animals, the consumers and terrestrial environmental compartment, but no conclusion could be made for the groundwater. The microtracer should be considered a dermal and respiratory sensitiser. In the current assessment, the FEEDAP Panel concluded that the additive is safe for turkeys for fattening at the maximum proposed supplementation level of 0.4 mg Cr/kg feed, but a margin of safety cannot be established. This conclusion can be extended to turkeys reared for reproduction, but cannot be extrapolated to other growing poultry species. The use of the additive according to the proposed conditions of use causes no concern for consumer safety. The conclusions made previously for user safety remain the same: the additive does not present a risk by inhalation, the additive is irritant to the eyes, not irritant to the skin and is not a skin sensitiser. The use of the additive is considered safe for the environment. The previous conclusion on efficacy remains valid.

Safety of the use of a microtracer with the feed additive consisting of chromium propionate (KemTRACE™ chromium) for all growing poultry species.

In the context of the FEEDAP opinion on the safety and efficacy of a feed additive consisting of chromium propionate (KemTRACE™ Chromium) of 18 March 2021, the EU Reference Laboratory for feed additives (EURL) was not in a position to recommend the method: proposed by the applicant for official control for the quantification of the organic chromium content in premixtures and feedingstuffs. The applicant subsequently proposed a new method of analyses, incorporating a tracer in the composition of a premix, which has been evaluated by EURL and recommended as official method for the quantification of the organic chromium content in premixtures and feedingstuffs. In view of the above, the Commission asked EFSA to issue a new opinion on the safety and efficacy of chromium proprionate (KemTRACE™ Chromium) as feed additive for all growing poultry species including the newly submitted information by the applicant that involves the use of the microtracer. The present opinion is limited to the assessment of the new information submitted by the applicant in support of safety of the proposed use of the microtracer in the composition of the premix. The FEEDAP Panel concluded that the use of the microtracer in the premixture, at the proposed level of use, does not present a risk for the target species and the consumer. The microtracer should be considered a dermal and respiratory sensitiser. Therefore, any exposure of users to the microtracer via skin or the respiratory tract is considered a risk. The use of the microtracer at proposed conditions of use is safe for the terrestrial environmental compartment, but no conclusion can be made for the groundwater. The addition of the microtracer in the premix/feedingstuffs is not expected to have any impact on the efficacy of the additive, and therefore, the previous conclusion on the efficacy is still valid.

Feed additives for methane mitigation: Modeling the impact of feed additives on enteric methane emission of ruminants-Approaches and recommendations.

Over the past decade, there has been considerable attention on mitigating enteric methane (CH4) emissions from ruminants through the utilization of antimethanogenic feed additives (AMFA). Administered in small quantities, these additives demonstrate potential for substantial reductions of methanogenesis. Mathematical models play a crucial role in comprehending and predicting the quantitative impact of AMFA on enteric CH4 emissions across diverse diets and production systems. This study provides a comprehensive overview of methodologies for modeling the impact of AMFA on enteric CH4 emissions in ruminants, culminating in a set of recommendations for modeling approaches to quantify the impact of AMFA on CH4 emissions. Key considerations encompass the type of models employed (i.e., empirical models including meta-analyses, machine learning models, and mechanistic models), the modeling objectives, data availability, modeling synergies and trade-offs associated with using AMFA, and model applications for enhanced understanding, prediction, and integration into higher levels of aggregation. Based on an evaluation of these critical aspects, a set of recommendations is presented concerning modeling approaches for quantifying the impact of AMFA on CH4 emissions and in support of farm-level, national, regional, and global inventories for accounting greenhouse gas emissions in ruminant production systems.

Comparison between effect of chitosan and Nano-chitosan as feed additives on cultured tilapia nilotica fish (Oreochromis niloticus)

Comparison between effect of chitosan and Nano-chitosan as feed additives on cultured tilapia nilotica fish (Oreochromis niloticus)