Current knowledge and future perspectives of the use of seaweeds for livestock production and meat quality: a systematic review

The effects of dietary macroalgae, or seaweeds, on growth performance and meat quality of livestock animal species are here reviewed. Macroalgae are classified into Phaeophyceae (brown algae), Rhodophyceae (red algae) and Chlorophyceae (green algae). The most common macroalga genera used as livestock feedstuffs are: Ascophyllum, Laminaria and Undaria for brown algae; Ulva, Codium and Cladophora for green algae; and Pyropia, Chondrus and Palmaria for red algae. Macroalgae are rich in many nutrients, including bioactive compounds, such as soluble polysaccharides, with some species being good sources of n-3 and n-6 polyunsaturated fatty acids. To date, the incorporation of macroalgae in livestock animal diets was shown to improve growth and meat quality, depending on the alga species, dietary level and animal growth stage. Generally, Ascophyllum nodosum can increase average daily gain (ADG) in ruminant and pig mostly due to its prebiotic activity in animal's gut. A. nodosum also enhances marbling score, colour uniformity and redness, and can decrease saturated fatty acids in ruminant meats. Laminaria sp., mainly Laminaria digitata, increases ADG and feed efficiency, and improves the antioxidant potential of pork. Ulva sp., and its mixture with Codium sp., was shown to improve poultry growth at up to 10% feed. Therefore, seaweeds are promising sustainable alternatives to corn and soybean as feed ingredients, thus attenuating the current competition among food-feed-biofuel industries. In addition, macroalgae can hinder eutrophication and participate in bioremediation. However, some challenges need to be overcome, such as the development of large-scale and cost-effective algae production methods and the improvement of algae digestibility by monogastric animals. The dietary inclusion of Carbohydrate-Active enZymes (CAZymes) could allow for the degradation of recalcitrant macroalga cell walls, with an increase of nutrients bioavailability. Overall, the use of macroalgae as feedstuffs is a promising strategy for the development of a more sustainable livestock production.     

The role of seaweed as a potential dietary supplementation for enteric methane mitigation in ruminants: Challenges and opportunities

Seaweeds are macroalgae, which can be of many different morphologies, sizes, colors, and chemical profiles. They include brown, red, and green seaweeds. Brown seaweeds have been more investigated and exploited in comparison to other seaweed types for their use in animal feeding studies due to their large sizes and ease of harvesting. Recent in vitro and in vivo studies suggest that plant secondary compound-containing seaweeds (e.g., halogenated compounds, phlorotannins, etc.) have the potential to mitigate enteric methane (CH₄) emissions from ruminants when added to the diets of beef and dairy cattle. Red seaweeds including Asparagopsis spp. are rich in crude protein and halogenated compounds compared to brown and green seaweeds. When halogenated-containing red seaweeds are used as the active ingredient in ruminant diets, bromoform concentration can be used as an indicator of anti-methanogenic properties. Phlorotannin-containing brown seaweed has also the potential to decrease CH₄ production. However, numerous studies examined the possible anti-methanogenic effects of marine seaweeds with inconsistent results. This work reviews existing data associated with seaweeds and in vitro and in vivo rumen fermentation, animal performance, and enteric CH₄ emissions in ruminants. Increased understanding of the seaweed supplementation related to rumen fermentation and its effect on animal performance and CH₄ emissions in ruminants may lead to novel strategies aimed at reducing greenhouse gas emissions while improving animal productivity.     

The effect of metal-containing nanoparticles on the health,performance and production of livestock animals and poultry

The application of high doses of mineral feed additives in the form of inorganic salts increases the growth performance of animals, but at the same, due to their low bioavailability, can contaminate the environment. Therefore, there is a need to find a replacement of administering high doses of minerals with an equally effective alternative. The application of lower doses of metal-containing nanoparticles with the same effect on animal production could be a potential solution. In the present review, zinc, silver, copper, gold, selenium, and calcium nanoparticles are discussed as potential feed additives for animals. Production of nanoparticles under laboratory conditions using traditional chemical and physical methods as well as green and sustainable methods – biosynthesis has been described. Special attention has been paid to the biological properties of nanoparticles, as well as their effect on animal health and performance. Nano-minerals supplemented to animal feed (poultry, pigs, ruminants, rabbits) acting as growth-promoting, immune-stimulating and antimicrobial agents have been highlighted. Metal nanoparticles are known to exert a positive effect on animal performance, productivity, carcass traits through blood homeostasis maintenance, intestinal microflora, oxidative damage prevention, enhancement of immune responses, etc. Metal-containing nanoparticles can also be a solution for nutrient deficiencies in animals (higher bioavailability and absorption) and can enrich animal products with microelements like meat, milk, or eggs. Metal-containing nanoparticles are proposed to partially replace inorganic salts as feed additives. However, issues related to their potential toxicity and safety to livestock animals, poultry, humans, and the environment should be carefully investigated.     

植物多酚的抗氧化机理及其在动物生产中的应用

肉及肉制品在加工及贮藏过程中易发生氧化而导致品质下降，在动物日粮中添加植物多酚可抑制脂肪及蛋白质氧化，进而提高肉及肉制品在加工及贮藏过程中的氧化稳定性。植物多酚因具有酚羟基结构而具有清除自由基的抗氧化作用，可提高动物机体及肉制品中抗氧化酶的活性，还可激活Nrf2/ARE信号通路从而提高肉制品在加工及贮藏过程中的抗氧化能力。将植物多酚添加到畜禽日粮中，可促进动物对饲料中营养物质的消化吸收，提高其生产性能，且可提高动物机体的抗氧化酶活性及总抗氧化能力，降低畜禽产品中丙二醛的含量，提高产品的质量，延长产品的货架期。文章介绍了植物多酚，包括黄酮类、酚酸类、非黄酮类化合物及其代表性化合物的结构，并阐述了其抗氧化性机理及其在动物生产中的应用，旨为研究利用植物多酚提高肉制品的氧化稳定性、安全性提供理论参考。     

唇形科植物提取物对单胃动物的抗氧化作用及其机制

动物在患病、应激或特殊生理条件下,机体内会大量产生自由基,自由基与机体内的脂质、ＤＮＡ等产生反应,可对动物造成氧化损伤。唇形科植物提取物中的抗氧化物主要活性成分是酚类化合物,它和抗坏血酸及类胡萝卜素能够阻止自由基引发的氧化伤害。本文阐述了唇形科植物提取物对猪、鸡体外和体内抗氧化作用的实例与抗氧化功能,分析了其抗氧化作用机制。     

动物氧化应激及其营养调控措施研究进展

动物机体内存在氧化还原平衡,正常状态下保持相对的稳态,当环境或自身状态发生改变时,这种平衡可能会被打破,进而引发机体氧化应激。研究发现,引起氧化应激的因素有很多：如环境因素、动物自身状态改变和外源致病菌以及病毒等,这些因素造成的氧化应激对动物的健康状况、生产性能和繁殖功能等方面会产生不同程度的影响,严重时甚至引发动物死亡,因此,寻求和添加安全有效的抗氧化制剂以调节动物氧化还原状态具有重要的现实意义。目前,针对动物氧化应激的营养性添加剂主要有益生菌、维生素、微量元素、激素类和植物类活性物质等。本文对引发动物氧化应激的主要原因和其对动物产生的影响进行了总结,并概括了具有缓解动物氧化应激功能的营养性饲料添加剂,以期为动物氧化应激和其缓解策略的进一步研究提供参考。     

Phenolic compounds as natural feed additives in poultry and swine diets: a review

Due to ban on using antibiotics in feed industry, awareness of using natural feed additives have led to a great demand. The interest of plants phenolic compounds as a potential natural antioxidant source has been considered in research community due to their predictable potential role as feed additives in poultry and swine production.However, the mode of action for their functional role and dosage recommendation in animal diets are still remain indistinct. Taking into account, the present review study highlights an outline about the mode of action of phenolic compound and their experimental uses in poultry and swine focusing on the growth performance, antioxidant function, immune function, antimicrobial role and overall health status, justified with the past findings till to date.Finally, the present review study concluded that supplementation of phenolic compounds as natural feed additives may have a role on the antioxidant, immunity, antimicrobial and overall production performance in poultry and swine.     

Polyphenol compounds in the chicken/animal diet: from the past to the future

Animal feed provides a range of antioxidants that help the body building an integrated antioxidant system responsible for a prevention of damaging effects of free radicals and products of their metabolism. Vitamin E is considered to be the main chain‐breaking antioxidant located in the membranes and effectively protecting them against lipid peroxidation. Recently, various polyphenol compounds, especially flavonoids, have received substantial attention because of their antioxidant activities in various in vitro systems. However, it was shown that flavonoid compounds are poorly absorbed in the gut and their concentrations in target tissues are too low to perform an effective antioxidant defences. The aim of the present paper is to review existing evidence about possible roles of various plant extracts provided with the diet in animal/poultry nutrition with a specific emphasis to their antioxidant activities.     

The influence of dietary chestnut and quebracho tannins mix on rabbit meat quality

Tannins were recently evaluated as feed additives in order to increase antioxidant compounds in animal diet, mainly to enhance resistance to lipid oxidation in meat. Rabbit meat is one of the most susceptible animal products, thus the main aim of this study was to evaluate the capacity of tannins to elongate shelf life of rabbit meat. Ninety hybrid rabbits were fed with three different diets: basal diet (control, C) and basal diet supplemented with 0.3% or 0.6% of tannins mix. Meat samples were refrigerated as raw at 4°C up to 11 days and analysed both as raw and cooked for physical‐chemical characteristics, fatty acids profile, lipid oxidation and antioxidant capacity. Results showed that dietary tannins affected meat colour of raw samples (mostly yellowness). Lipid peroxidation (TBARS) of raw samples was lower in tannins group than C group; a further inhibition of peroxidation was showed also in cooked samples only by the highest dose of tannins mix. Moreover, antioxidant capacity (ABTS) of raw samples increased with the percentage of tannins. In conclusion, supplementation with 0.6% of tannins mix seems to positively affect the lipid peroxidation and antioxidant capacity of meat without modifying the intrinsic characteristics of rabbit meat.     

Effect of dietary microbially produced gamma‐linolenic acid and plant extracts on enzymatic and non‐enzymatic antioxidants in various broiler chicken organs

Plant extracts and fungal fermented feed with gamma‐linolenic acid‐rich microbial oils are perspective additives for use in animal nutrition as appetite and digestion stimulants, stimulants of physiological functions, for the prevention and treatment for certain pathological conditions, and as antioxidants. The activity of antioxidant enzymes and the level of reduced glutathione were measured in the plasma and in liver, heart and kidney mitochondria after 42 days of feeding broiler chickens both regular and combination diets. These were selected based on our previous experience. The administration of agrimony and gamma‐linolenic acid resulted in a significant decrease in superoxide dismutase activity in all four bodies in contrast to plant extracts. We conclude that the decrease in activity is due to decreased production, and hence dismutation, of superoxide radicals to peroxides followed by lower activity of glutathione peroxidase, which was not seen in the case of only plant extract administration. Generally, higher glutathione reductase activity would be in response to increased demands on reduced glutathione as a cofactor for the reaction catalysed by glutathione peroxidase and the utilization of glutathione itself. However, measured levels of reduced glutathione showed no change. The results argue against any oxidative stress conditions. The application of agrimony extract appears to be suitable for the antioxidant effect against peroxidation of gamma‐linolenic acid. As the efficacy of measuring the effects of diets on the oxidative stability of meat caused by selected antioxidant enzymes is rather low, additional data from the experiment will be processed to clearly assess the influence of this combination of diets.     

Herbal plants and their derivatives as growth and health promoters in animal nutrition

The purpose of this review is to summarize the effectiveness, modes of action and commercial application of herbal plants and their derivatives as growth promoters for animal. Feed supplements are a group of feed ingredients that can cause a desired animal response in a non-nutrient role such as pH shift, growth, or metabolic modifier (Hutjens, 1991). Common feed additives used in animal diets include immunostimulators, antimicrobials, antioxidants, pH control agents and enzymes. Herbal plants, are a new class of growth promoters and in recent years this feed additives have gained extensive attention in the feed industry. They are a wide variety of herbs, spices, and products derived thereof, and are mainly essential oils. Although numerous reports have demonstrated antioxidative and antimicrobial and immune stimulation efficacy in vitro, respective experimental in vivo evidence is still quite limited. A limited number of experimental comparisons of herbal plants feed additives with antibiotics or organic acid have suggested similar effects on the animal gut microflora. Gut microflora has significant effects on host nutrition, health, and growth performance by interacting with nutrient utilization and the development of gut system of the host. In addition, some phytogenic compounds seem to promote intestinal mucus production. However, the future of using herbs in animal feeding will in great measure depend on the knowledge of chemical structure, their value and characteristics of practical herbs or their extract physiological needs and well-being of animal, and, above all on consumer’s preferences and expectations.     

植物源性抗氧化剂的应用及其作用机制

植物源性抗氧化剂是一类来源于植物,具有抗氧化功能的物质,在养殖业中作为饲料添加剂被应用,具有来源广泛、高效、安全和无残留等特点。本文主要综述了此类抗氧化剂在畜牧业中常用的种类以及在生产中的应用效果,并总结了其作用机制的研究进展,为今后更广泛深入地开展植物源性抗氧化剂的研究与应用,进一步阐明深层次作用机理提供参考。     

Strategies to modulate the intestinal microbiota and their effects on nutrient utilization,performance, and health of poultry

Poultry is widely produced and consumed meat global y. Its demand is expected to continue increasing to meet the animal protein requirement for ever-increasing human population. Thus, the chal enge that poultry scientists and industry face are to produce sufficient amount of poultry meat in the most efficient way. In the past, using antibiotics to promote the growth of poultry and manage gut microbiota was a norm. However, due to concerns over potential fatalistic impacts on food animals and indirectly to humans, their use as feed additives are banned or regulated in several jurisdictions. In this changed context, several alternative strategies have been proposed with some success that mimics the functions of antibiotics as growth promoters and modulate gut microbiota for their beneficial roles. These include the use of probiotics, prebiotics, organic acids, and exogenous enzyme, among others. Gut microbiota and their metabolic products improve nutrient digestion, absorption, metabolism, and overal health and growth performance of poultry. This paper reviews the available information on the effect of feed additives used to modulate intestinal microbiota of poultry and their effects on overal health and growth performance. Understanding these functions and interactions wil help to develop new dietary and managerial strategies that wil ultimately lead to enhanced feed utilization and improved growth performance of poultry. This review wil help future researchers and industry to identify alternative feed ingredients having properties like prebiotics, probiotics, organic acids, and exogenous enzymes.     

Novel and disruptive biological strategies for resolving gut health challenges in monogastric food animal production

Use of feed antibiotics as growth promoters for control of pathogens associated with monogastric food animal morbidity and mortality has contributed to the development of antimicrobial resistance, which has now become a threat to public health on a global scale. Presently, a number of alternative feed additives have been developed and are divided into two major categories, including 1) the ones that are supposed to directly and indirectly control pathogenic bacterial proliferation; and 2) the other ones that are intended to up-regulate host gut mucosal trophic growth, whole body growth performance and active immunity. A thorough review of literature reports reveal that efficacy responses of current alternative feed additives in replacing feed antibiotics to improve performances and gut health are generally inconsistent dependent upon experimental conditions. Current alternative feed additives typically have no direct detoxification effects on endotoxin lipopolysaccharides(LPS) and this is likely the major reason that their effects are limited. It is now understood that pathogenic bacteria mediate their negative effects largely through LPS interactions with toll-like receptor 4, causing immune responses and infectious diseases. Therefore, disruptive biological strategies and a novel and new generation of feed additives need to be developed to replace feed antibiotic growth promoters and to directly and effectively detoxify the endotoxin LPS and improve gut health and performance in monogastric food animals.     

Alpha‐lipoic acid: An inimitable feed supplement for poultry nutrition

Alpha‐lipoic acid (ALA) is a multifunction antioxidant that is produced in small amount by cells as well as its dietary provision facilitates fatty acid mobilization, energy expenditure as well as can scavenge free radicals in poultry birds. It exists in oxidized as well as reduced form, characterized by growth promoting, anti‐inflammatory, antioxidative, immunostimulatory, and hypocholesterolemic properties when fed as dietary supplement to farm animals particularly chicken birds. Recently, several studies reported that dietary supplementation of ALA can influence growth performance indicators, immunological, biochemical characteristics, lipid metabolism, and oxidative stress as well as increase antioxidant potential and storability of poultry meat and meat products. Accordingly, this paper adds the reviews and discusses the outcomes of studies documenting the effect of lipoic acid dietary fortification on growth performance, biochemical, and immunological characteristics as well as the effects on lipid peroxidation of fresh meat and meat‐based products. Furthermore, this paper also describes the possibilities of utilization of ALA as a feed additive in poultry nutrition to improve the growth performance of poultry as well as meat quality of resultant chicken birds.     

欧盟禁用饲料药物添加剂的历史和法规

欧盟考虑到抗生素耐药性的发展和抗生素耐药基因可能从动物到人微生物的转移,决定从2006年1月1日起禁止抗生素作为生长促进剂,甚至还建议禁止在动物饲料中全面使用所有的抗菌剂。收集和整理欧盟饲料药物添加剂的禁用清单和法规,介绍欧盟禁用饲料药物添加剂的历史及其对动物健康的影响,以期为中国饲料药物添加剂的使用和管理提供借鉴和参考。     

Ochratoxin A: Carryover from animal feed into livestock and the mitigation strategies

This review aims to highlight the effects of ochratoxin A (OTA) in the feed of meat-producing animals. The accumulation of OTA in feed and its distribution in various farm animals were compared and evaluated. Primarily, the oral administration of OTA-contaminated feed and the predisposition in an animal''s vital organ were critically examined in this work. The collated reports show that OTA directly associated with endemic nephropathy and its high concentration leads to degeneration of liver cells, and necrosis of intestinal and lymphoid tissues. At present, limited reports are available in the recent literature on the problems and consequences of OTA in feed. Therefore, this review focused on the OTA carryover from feed to farm animals and the interaction of its secondary metabolites on their biochemical parameters. Hence, this report provides greater insights into animal health related to OTA residues in meat and meat products. This article also explores mitigation strategies that can be used to prevent the carryover effects of OTA in livestock feeds and the effects in the food chain.     

植物提取物添加剂在动物营养中的应用及其机制的研究进展

植物提取物添加剂具有提高动物生产性能、无残留和无抗药性的特点,能够为畜禽养殖业高效生产安全、健康、营养的食品提供保证.本文综述了植物提取物添加剂的抗菌和抗氧化作用,并总结了其在猪禽上的应用研究和影响其使用效果的因素.     

不同饲料添加剂对肉牛生长发育与产肉性能影响的研究

试验旨在研究两种添加剂在相同配方下对肉牛各组织器官生长发育的影响。选择健康的新疆周岁褐牛公牛30头,随机分为3组,试验组与对照组日粮相同,试验Ⅰ组精料中添加1%的肉牛育肥饲料复合添加剂,试验Ⅱ组精料中添加0.2%的巴尔吡尔。对肉牛骨骼与脏器组织生长发育、产肉性能进行测定与分析。结果表明,与对照组相比,试验Ⅰ、Ⅱ组在腰角宽、髋宽上差异显著(P<0.05),另外,能显著增加试验Ⅱ和试验Ⅰ组的血液与复胃的重量(P<0.05);具有增加胴体重与高档、优质肉产量,提高屠宰率,调控不同部位肌肉组织生长的效果。与对照组相比,试验Ⅰ、Ⅱ组在育肥增重、胴体、净肉、高档优质肉销售收益上获利增加额分别为42.7、130.6、142.22、141.6和-15.8、38.2、76.1、149.7元。因此,两种添加剂对动物的生长发育、肌肉、骨骼、脂肪组织具有一定的调控作用,巴尔吡尔添加剂具有增加肉牛脂肪代谢,降低体脂的功效,可作为安全、高效饲料添加剂应用于肉牛育肥生产中。     

植物提取物在肉羊生产中的应用

植物提取物因具有无残留、无抗药性、无毒副作用等优点而被作为新型绿色饲料添加剂广泛应用于畜禽养殖中,为畜禽健康、安全生产以及为人类提供优质畜产品方面起到了重要作用。本文综述了植物提取物的主要生物学活性成分,并着重阐述了植物提取物对肉羊生长性能、抗氧化能力和瘤胃发酵等的影响及其作用机理,旨在为天然植物源饲料添加剂的研发并在肉羊养殖中的应用提供参考依据。