Antibiotic Alternatives in Poultry and Fish Feed

The poultry industry is one of the significant hubs of the livestock industry and the world's largest food industry. In the last 50 years, it has become common to observe poultry antibiotic feeding to treat disease and growth. Antibiotics inhibit the growth of toxic and beneficial microorganisms. They are used as growth promoters when given in adjunctive therapy. The Centers for Disease Control and Prevention (CDC) estimates that fifty million pounds of antibiotics will be produced each year in the USA. Forty percent of the total antibiotics produced will be used in agriculture. 11 million pounds are used for the poultry sector and 24 million for domestic and wild animals. Ciprofloxacin, chloramphenicol, enrofloxacin, oxytetracycline, tylosin, tetracycline, virginiamycin, tilmicos, nitrofuran and sulfamids are used as growth promoters in the poultry industry globally. Antibacterial residues are found in various parts of poultry birds, e.g., kidney, heart, gizzard, liver, chest, thigh muscles, albumin and egg yolk. These residues may directly or indirectly produce many health concerns in human beings, such as toxic effects in the liver, brain, bone marrow, kidney, allergic reaction, mutagenicity, reproductive abnormalities and gastrointestinal tract leading to indigestion. In addition, resistant strains of pathogenic microbes pose an indirect threat to antibacterial residues that can spread to humans and contaminate residual fertilizers used as plant fertilizers. This chapter describes the benefits and contraindications of antibiotics used as growth promoters and the toxic effects of antimicrobial residues in poultry and humans.

Modern poultry industry faces the everlasting challenge of the growing demand for high-quality, low-priced food without compromising general hygiene, health, and welfare standards. To exploit optimal growth potential, antibioticsupplemented feeds were implemented in the past decades. But later on, alternative strategies to trigger the productive characteristics of birds were proposed, including the use of phytochemicals. Phytobiotics are herbs and their derivatives, endowed with many beneficial effects. Herbs and their products enhance feed intake by mitigating intestinal damage, strengthening intestinal integrity, compensating nutritional needs for local and general immune response, reducing the concentration of pathogenic microflora, and preventing local inflammatory response. This form of feed manipulation recently gained interest in the poultry sector due to the lack of side effects, immune system modulation boosting, and stress tolerance. On the other hand, several types of research highlighted the potentially harmful effects of some herbs and their metabolites. This raised concerns among consumers about their safety and implications as feed supplements or medicines. This chapter will provide insights into phytobiotics, their role in immunity and growth, and the possible risks of herbal supplemented feeds in the poultry sector.

Poultry ventures have progressed quickly over the last three decades. Therefore, curative or growth-promoting antibacterial agents have been utilized extensively. Because of increasing bacterial resistance towards antibiotics and, consequently, accumulation of antibacterial residues in chicken products and increased consumer’s demand for products without antibacterial residues, alternative solutions that could substitute antibiotics without affecting productivity or product quality should be attempted. Recently, natural replacements such as ginger, etheric oils, organic acids, garlic prebiotics, immune stimulants and plant extracts were used to improve productiveness, and body performance, prevent pathogenic microorganisms, and reduce antibacterial activity usage in poultry manufacturing. The utilization of a single alternative or a combination of variable replacements and perfect surveillance and flock health might improve the profits and sustain the productivity of poultry. This chapter aimed at summarizing the recent knowledge and information regarding the utilization of ginger and its derivatives as natural alternatives or supplements in poultry feed and their impacts on poultry productivity, meat and egg traits in addition to economic efficacy.

The recent trend toward banning the use of antibiotics in poultry feed as a growth promoter directs the scientific community to look for natural alternatives with potential growth-promoting and immunomodulating properties. Phytogenic feed additives have attracted significant attention as alternatives to antibiotics to improve growth performance and enhance immune responses. They have anti-inflammatory, antioxidant, antiviral, and antifungal properties, depending on their chemical structure and composition. Scientists are using these non-conventional ingredients as feed additives in the form of oil or powder. Essential oils (EO) are volatile liquids produced from aromatic plants. Their application has gained momentum in controlling cholesterol as free radical scavengers, anti-microbials, antifungals, and stimulants of digestive enzymes. EO's possible antimicrobial features against harmful pathogens are primarily associated with the high content of volatile components in oils. The current chapter highlights the beneficial impact of cinnamon oil as a feed additive on poultry growth performance, meat quality, carcass traits, and its hypo-cholesterolaemic impact, antioxidant act, microbiological aspects, and immunomodulatory effects.

Production of safe and healthy poultry diets of high profitability is the central aim of poultry men. This safety is achieved by using natural products as growth stimulants. Natural feed additives such as medicinal products derived from herbs and spices are mainly used in the poultry feed industry as appetite and enzyme secretion stimulants. The use of clove (Syzygium aromaticum) and its derivatives has lately received much greater attention as an alternative to traditional antibiotics. The clove exhibited strong antibacterial, antioxidant, anti-septic and anti-inflammatory properties and appetite and digestion stimulants. The clove and its derivatives contain bioactive components, including eugenol, eugenyl acetate, ᵦ-caryophyllene, salicylic acid, ferulic acid, caffeic acid, ellagic acid, kaempferol, methyl amyl ketone, humulene, gallotannic acid, and crategolic acid that have beneficial effects. Eugenol is the main bioactive component present in the clove. The potential advantages of utilizing clove extracts in poultry diets include improved growth performance, egg production and feed conversion ratio, enhanced digestion, and down-regulated disease incidence. From the available literature, clove and its essential oil is one of the beneficial plant extracts to increase growth performance in poultry by improving the intestinal microbiota population. Clove extract contains various molecules (principally eugenol) that have self-biological activities in poultry physiology and metabolism. This chapter includes information on clove and its derivatives in poultry nutrition.

Punica Grantum L is an ancient, magical and distinctive fruit. It is local to the Mediterranean basin and has been broadly utilized in traditional pharmaceuticals in numerous nations. The extracts collected from various parts (peels, seeds, juice and flowers) of this natural fruit can be used as multiple additives for practice because of its polyphenolic contents. Polyphenols found in P. Grantum have been shown to have various pharmacological activities such as anti-inflammatory, antioxidant, antimicrobial, anti-diarrheal, immunomodulatory, anti-carcinogenic, and wound healing promotors. Moreover, they are reported to have anti-cestodial, anti-nematodal and anti-protozoan activities. P. Grantum L or its by-products supplementation can play a major role in poultry nutrition by enhancing immunity, scavenging free radicals, and inhibiting antimicrobial activity, leading to improved poultry performance. Owing to its functions above, it can be a potential substitute for modulating immune functions and gut microbiota to relieve diarrhea and enteritis, preventing colibacillosis and coccidiosis in chickens. Moreover, it is reported that polyphenols and tannins of P. Grantum act as an antioxidant by scavenging reactive oxygen species and preventing lipid oxidation and inflammatory molecule production. This chapter highlights the work done in the recent past on P. Grantum. Despite the voluminous pharmacological properties of P. Grantum, its usage in the chicken ration is limited. So, this chapter aims to broaden the information of researchers, veterinary advisors, and poultry nutritionists to recommend P. Grantum as a safe, natural added substance in poultry feed to substitute the synthetic additives for nourishment purposes.

Chicory (Cichorium intybus) is a perennial herb that belongs to the Asteraceae family. Certain species are grown and used as fried, dry salad leaves, roots, or chicons as a substitute for coffee additives. It is also cultivated as forage that can be used in animal feeding. In addition, chicory has significant effects on animal and human health and has various biological activities, such as immunostimulant, antimicrobial, antioxidant, hyperlipidemic, anti-inflammatory, and antidiabetic activity. Chicory extracts protect the liver by lowering the levels of liver enzymes, e.g., aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase (ALP). The chicory plant plays a key role in protecting hepatocytes and other liver cells. It is used as an antimicrobial agent in vitro and in vivo against certain pathogenic bacteria species. Chicory improves immunity and feed efficacy by reducing pathogenic microorganisms in the gastrointestinal tract. Cichorium intybus roots were also used to alleviate slight intestinal disturbances, including the sense of flatulence, full abdomen, transient appetite loss, and indigestion. This chapter describes the role of chicory plants in promoting growth when used as feed additives in poultry feed. It also explains the mechanisms of action of chicory extracts and their role as a liver protector for poultry.

Herbs or medicinal plants have gained significant attention due to their bioactive compounds that could act as antioxidants, anti-inflammatory, antimicrobial, anticancer agents, etc. Psyllium husk (Plantago ovata) is an Indian native herb. The water-loving (hydrophilic) mucilloid and water-soluble fiber derived from Plantago ovata have been used in traditional Indian Ayurvedic medicine as a crucial remedial mediator of constipation. Psyllium is a rich source of fiber and has many other remedial properties, including lowering the level of cholesterol, raising energy, relaxing inflammation, serving as an antidiarrhoeal, antidiabetic, laxative, and also used in hemorrhoid therapy, and as weight loss agent. The blood serum cholesterol-lowering property of the psyllium husk had drawn the researchers' main focus; thus, Psyllium is thought to be a plausible herbal agent helpful in treating hyperlipidemia. In various animal models, cholesterol levels are reduced by binding Psyllium husk with bile acids in the intestinal, thereby lowering its absorption rate. Screening literature has demonstrated that Psyllium husk could be utilized as an antidiarrheal mediator to cope with the diarrheal symptoms associated with poultry farming disorders. Additionally, Psyllium may also benefit various poultry species' production and growth traits. The present chapter explored Psyllium's potential responsibility for coping the hypercholesterolemia and the uses of psyllium husk as a safe feed additive in poultry farming for organic production and lowering cholesterol in meat and for production of functional foods.

 Taraxacum officinale, also known as dandelion herb, is a popular medicinal and therapeutic herb used for many years and is mostly raised in Europe, Asia, North and South America. It contains several nutrients and bioactive substances, especially the leaves and roots of this herb, which are a rich source of fiber, lecithin, choline, and micronutrients such as minerals (potassium, magnesium, calcium, zinc, etc., iron) and vitamins (A, C, K, and B-complex). The root has been commonly used for digestive and liver problems due to its stimulatory effects on the production of bile and detoxification functions. The leaves of dandelion have stimulatory functions on the digestive system and possess diuretic effects. Furthermore, several studies have shown that dandelion leaves can enhance the growth and productivity of poultry. Various functions on the intestinal mucosa have been reported, including the effects on the architecture of villi, villus height/crypt depth ratio, and cellular infiltration. This herb also has various beneficial functions, such as immunomodulatory effects, stimulation of the digestive system and insulin activation, enhancing the metabolism of androgens, and acting as a probiotic, antiangiogenic, antineoplastic and demulcent. Moreover, the dandelion herb can treat indigestions and hepatitis B infection. Due to the lack of studies on the effects of dandelion, further research has to be conducted to exploit the medicinal properties of this herb for its beneficial health impact on humans, pet and livestock animals (e.g., poultry) nutrition.

Since the early 1950s, antibiotics have been used in poultry for improving feed efficiency and growth performance. Nevertheless, various side effects have appeared, such as antibiotic resistance, antibiotic residues in eggs and meat, and imbalance of beneficial intestinal bacteria. Consequently, it is essential to find other alternatives that include probiotics that improve poultry production. Probiotics are live microorganisms administered in adequate doses and improve host health. Probiotics are available to be used as feed additives, increasing the availability of the nutrients for enhanced growth by digesting the feed properly. Immunity and meat and egg quality can be improved by supplementation of probiotics in poultry feed. Furthermore, the major reason for using probiotics as feed additives is that they can compete with various infectious diseases causing pathogens in poultry's gastrointestinal tract. Hence, this chapter focuses on the types and mechanisms of action of probiotics and their benefits, by feed supplementation, for poultry health and production.

The aquaculture industry has shown rapid growth over the last three decades, especially with improving the farming systems. However, the rapid expansion and intensification practices in the aquaculture sector have been marred by increased stress levels and disease outbreaks, and subsequently, high fish mortality. Excessive use of veterinary drugs and antibiotics in aquaculture poses a great threat to human and aquatic animals' health, as well as to the biosystem. Furthermore, exposure to various pollutants such as industrial effluents and agricultural pesticides may cause devastating toxicological aspects of fish and adversely affect their health and growth. Besides, with a growing world population, there is a growing interest in intensifying aquaculture production to meet the global demand for nutritional security needs. Uncontrolled intensification of aquaculture production makes aquatic animals both vulnerable to, and potential sources of a wide range of hazards include pathogen transmission, disease outbreak, immunosuppression, impaired growth performance, malnutrition, foodborne illness, and high mortality. Plant-derived compounds are generally recognized as safe for fish, humans, and the environment and possess great potential as functional ingredients to be applied in aquaculture for several purposes. Phytogenic additives comprise a wide variety of medicinal plants and their bioactive compounds with multiple biological functions. The use of phytogenic compounds can open a promising approach towards enhancing the health status of aquatic animals. However, further invivo trials are necessary under favorable conditions with controlled amounts of identi-fied bioactive compounds along with toxicity testing for fish safety towards a realistic evaluation of the tested substance efficacy.

Aquaculture is a growing sector due to the high rising demand for fish, shrimp, oysters, and other products, which is partially conflicted by various infectious diseases. The infectious diseases affecting the production and inducing high mortalities cause substantial economic losses in this sector. Also, parasitic infections may induce severe mortality and morbidity in fish farms. Therefore, most farmers apply several kinds of antibiotics to control the problems induced by bacterial diseases and, to some extent, parasitic infections. The extensive usage of antibiotics to control or prevent pathogens may lead to the development of pathogenic resistant strains that might cause hazards to human health. Besides, there is a global trend toward reducing the application of antibiotics in aquaculture farms. Thus, there is a great effort to discover new natural and safe products with pharmaceutical properties, such as natural essential oils (EO). Essential oils are secondary metabolites of many plants (roots, flowers, seeds, leaves, fruits and peels) and their molecular structures provide a high antimicrobial and antiparasitic efficiency against pathogens. Consequently, it is essential to provide sufficient knowledge about the mode of action of EO against fish parasites and its future applications and directions in aquaculture.

 Antimicrobial peptides (AMPs) are the vital constituents that stimulate the innate immune defense system against pathogens and perform several biological activities, which provide the first defensive line against infectious diseases. Owing to their unique structure, they can be utilized as a therapeutic strategy for infectious diseases in fishes. Several kinds of AMPs are reported in fishes with broad-spectrum antimicrobial properties. Besides, the bacterial cells cannot develop resistance strains against these cationic compounds with low molecular weight. Thus, AMPs may be considered an alternative to antibiotics to prevent or control infectious diseases in aquaculture. It is essential to provide sufficient knowledge about the mode of action of AMPs against fish pathogenic agents and their future applications.