SEAWEEDS AS NOVEL FEED ADDITIVE FOR BROILERS
Suresh.C1* and Sujatha2
- Corresponding author & Assistant Professor and Head, Veterinary University Training & Research Centre, Nagapattinam, India-611001
- Assistant Professor, Farmers Training Centre, Tiruvarur, India – 610 004
Tamil Nadu Veterinary and Animal Sciences University, Chennai, Tamil Nadu, India-600051
*-Corresponding Author Email I.D:drsureshthambi@gmail.com
ABSTRACT
Seaweeds are rich source of carbohydrates, protein, minerals, vitamins, and dietary fibres with reasonably well balanced amino acid profiles and a distinctive combination of bioactive substances. Hence, seaweeds can be used in poultry feed. Seaweeds are macroalgae that often grow in the littoral zone in wide variety of sizes, colours, forms, and compositions. They consist of the Phaeophyta (brown algae), Rhodophyta (red algae), and Chlorophyta (green algae). Seaweeds have long been used as poultry feed. Seaweeds are continuously subjected to a variety of abiotic stimuli, including pathogenic microorganisms, desiccation, sunshine, osmotic stress, and severe temperatures. As a result, seaweeds have created defense mechanisms to withstand and survive these demanding circumstances. In addition to sulphated polysaccharides, organic acids, pigments, and phenolic compounds also create a variety of other special bioactive chemicals that have antiviral, antibacterial, and antioxidant properties. Kappaphycus alaverezii, Sargassum wightii, Turbinaria ornata, Gracilaria edulis and Gracilaria verrucosa species were suitable for livestock and poultry feeding owing to their availability, cost and package of practices developed for cultivation. Seaweeds have multiple bioactive compounds; the biofucntional properties of these compounds should be exploited favorably to augment the productivity in broiler.
Keywords: Seaweed, Tamil Nadu, Broiler, Feed additive
INTRODUCTION
Seaweeds are macroalgae that often grow in the littoral zone in wide variety of sizes, colours, forms, and compositions. They consist of the Phaeophyta (brown algae), Rhodophyta (red algae), and Chlorophyta (green algae). Seaweeds have long been used as poultry feed. According to the species, the moment of collection, the habitat, and environmental factors like water temperature, light intensity, and nutrient concentration in the water, they have a highly varying nutrient composition. Suresh et al. (2023) reported that only five Kappaphycus alaverezii, Sargassum wightii, Turbinaria ornata, Gracilaria edulis and Gracilaria verrucosa species were suitable for livestock feeding owing to their availability, cost and package of practices developed for cultivation rather than collection among 26 seaweeds taken for his study in Tamil Nadu. They have a sizable amount of water in them. Except for the amino acids containing sulphur, seaweeds are lacking in the majority of essential amino acids. Seaweeds contain 10–20 times more minerals than terrestrial plants and concentrate minerals from seawater. They have very little lipid content (1–5%), but the majority of that lipid is made up of polyunsaturated n-3 and n-6 fatty acids. Due to their size and ease of collecting, brown seaweeds have received greater research attention and are used more frequently than other species of algae for poultry nutrition. Due to their lower protein content (up to about 14%) and higher mineral content, brown algae have less nutritional value than red and green algae, although they do contain certain bioactive compounds. Alginates, sulphated fucose-containing polymers, and laminarin are found in brown algae; agars, carrageenans, xylans, sulphated galactans, and porphyrans are found in red algae; and xylans and sulphated galactans are found in green algae.
Among Phaeophyta, Sargassum wightii and Turbinaria ornata were available throughout the year in the east coast of Tamil Nadu. Sargassum ilicifolium and Dictyota barteyresiana were available throughout the year except April to June (Suresh et al., 2023). Brown algae have exceptionally flexible stems that enable them to endure the frequent beating of the waves. They are found predominantly in shallow seas or on rocks along the shore (Ghosh et al., 2012). Brown seaweeds have received more research attention and are used more frequently than other species of algae for animal feeding because of their larger size and ease of collecting. The largest seaweeds are brown algae, which may grow up to 35–45 m in length for some species and have a wide range of shapes. According to Murty and Banerjee (2012), the most prevalent genera include Ascophyllum, Laminaria, Saccharina, Macrocystis, Nereocystis, and Sargassum.
SCOPE
Seaweeds are rich source of carbohydrates, protein, minerals, vitamins, and dietary fibres with reasonably well-balanced amino acid profiles and a distinctive combination of bioactive substances. Hence, seaweeds have been used in poultry feed. The nutritional value of animal feed products has improved as a result of recent improvements in feed processing technology (Piconi, 2020 and Comtex, 2020). The market for animal nutrition is primarily being driven by an increase in the demand for poultry feed, which accounts for around 47% of global consumption (Comtex, 2020). The main factors boosting the animal feed additive industry include rising consumer awareness of the quality of chicken meat, recent outbreaks of poultry diseases, and the use of poultry meat and egg products as affordable sources of protein.
FUCTIONAL PROPERTIES OF SEA WEED
Seaweeds provide polyunsaturated fatty acids, pigments, and complex carbohydrates that have prebiotic properties and are recognized to be good for poultry health. It was observed that the chemical makeup of various seaweeds varies greatly, depending on the species, the location and time of collection, the amount of light and heat present, and the nutrient levels in the environment and saltwater. Misurcova (2011) stated that brown seaweeds feature a variety of bioactive chemical compounds, their nutritional value is often lower than that of red and green seaweeds. Brown seaweeds can accumulate iodine over 30,000 times more than that found in seawater (1500-8000 ppm vs. 0.05 ppm, respectively) and are rich in minerals (14%-35% dry matter). Peng et al. (2015) reported that red seaweeds may have higher protein concentrations (10%–50% dry matter) and lower iodine concentrations (0.03%–0.04%). When compared to brown seaweeds, green seaweeds like Ulva spp. may have higher protein content (up to 15%). For the production of seaweed meal, the post-harvesting activities must be finished as soon as possible to avoid contamination, notably by moulds. Seaweeds are often dried and powdered to very fine particles (between 300 and 900 m) for use as a supplement in poultry diets. Drying should not go beyond 50–70 °C in order to maintain the bioactivity of the metabolites in seaweeds (El-Deek and Brikaa, 2009).
EFFECT OF SEA WEEDS ON BROILER PERFORMANCE
Green Seaweeds
In the diets of broiler chickens, the abundant green seaweed Ulva spp. has been intensively researched as a replacement feed ingredient. Body weight gain (BWG) in broilers increased numerically when given 3% U. lactuca instead of 1% corn in the feed between 12-33 days of post-hatch, increasing the yield of breast muscle and dressing percentage. These improvements were due to the availability of soluble fibres and essential amino acids such methionine and cysteine, which contain Sulphur (Abudabos et al., 2013). Incorporating 3.0% U. lactuca considerably decreased the amount of belly fat (associated with triglycerides and cholesterol) in the treated birds. However, production traits like feed intake (FI), body weight gain (BWG), and feed conversion ratio (FCR) were comparable between treated and control birds. Up to 3% of U. lactuca at lower inclusion levels did not show harmful or anti-nutritional effects on broiler health (Abudabos et al., 2013). However, it was discovered that adding U. rigida at 4% and 6% as a prebiotic feed addition to a broiler diet improved FI, FCR, and reduced mortality (Markovic et al., 2009 ). The surface area available for absorption and the capacity for digestion both increased with increasing intestinal villi length, which also produced a bigger intestinal surface area and enhanced brush-border enzyme activity. In comparison to control, Ulva spp. supplemented treatments dramatically reduced serum levels of total cholesterol and triglycerides (Canedo-Castro et al., 2019). The variations in results between these trials with Ulva spp. in the diet may be related to elements like the quantity of seaweed supplemented, the purity of the seaweed, the drying method, particle size, different meal preparation techniques, and differences across species. Any meal made from seaweed should take into account all of these factors. However, the levels of inclusion in the diet are often low (up to 6%), which appears to be a common characteristic. The seaweeds don’t replace feed on their own, but when provided at reduced rates as supplements or prebiotics, they help broilers grow quicker and with better quality by enhancing their health and resilience to disease.
Brown Seaweeds
Alginates and fucoidans, which are known to have a variety of biological actions including anti-coagulant, anti-inflammatory, anti-viral, and anticarcingenic effects, are two functional polysaccharides that are abundant in brown algae. The performance of broilers has been tested using these components of seaweed as feed additives. For instance, the nutritional value of by-products from the brown seaweed Undaria pinnatifida in broiler diets has been studied. The by-products of seaweed that do not grow from an apical point and are sections of thalli (plant parts that cannot be differentiated into separate parts such as stem, leaves, and roots) are not eaten as food. When brown seaweed byproducts were added to the broiler diet at a level of 0.5%, it increased body weight gain, improved blood serum profiles, boosted immunological responses, and decreased mortality rates when compared to the control diet. In the liver, breast, and drumstick tissues, basal diet supplementation with 100 and 200 mg/kg of a fucoxanthin extract raised catalase (CAT), superoxide dismutase (SOD), and glutathione (GSH) levels while lowering malondialdehyde (MDA) levels. These findings illustrated that fucoxanthins might be employed to control antioxidant metabolism and strengthen broiler immune systems (Gumus et al., 2018).
It is generally known that antioxidant status of broiler affects their ability to fight off numerous illnesses, maintain good health, and operate productively and reproductively (Surai, 2002). In a study, broiler performance, average daily gain (ADG), FCR, antioxidant capacity, and immune status were all improved when broiler diets were supplemented with polymannuronate, a brown seaweed derivative, at inclusion levels of 0.1%, 0.2%, 0.3%, and 0.4% (Choi et al., 2014). This suggested that chemicals from brown seaweed could help broiler chickens perform better and have stronger immune systems and antioxidant capacities.
The reduction in the effects of prolonged heat stress caused by the addition of Ascophyllum nodosum (A. nodosum, 0.05% of feed) to broiler feed while having no detrimental effects on growth and feed conversion suggests that this type of feed supplementation can be used to improve bird immunity during heat stress events in poultry production. Climate change has increased the frequency of meteorological occurrences that result in heat exhaustion. Furthermore, because chicken production frequently takes place in places of the world where temperatures can reach 50 °C, it would be challenging to pass on the costs of cooling with slim profit margins. As a result, including A. nodosum in poultry diets at modest inclusion levels can lower the need for cooling poultry buildings.
In a recent study, Kumar (2018) explored the results of adding Sargassum wightii to broiler diets. Body weight, Feed intake, Feed conversion ratio, and meat quality were all improved by dried S. wightii powder at 1%, 2%, 3%, and 4%. Dietary inclusion of 1% and 2% Sargassum enhanced total serum proteins, albumin, calcium, phosphorus, and triglyceride levels in treated birds while lowering blood plasma cholesterol and globulins. The inclusion of 1% or 2% Sargassum powder had the best supplementing effects, according to the his findings. In comparison to controls, Sargassum increased food palatability while showing higher feed intake, improved digestibility, and intestinal absorption, all of which improved body weight gain.
The meat quality and carcass yield of treated birds were subsequently enhanced by a higher FCR, resulting in cost effectiveness. Saponins, hemicelluloses, mucilage, tannins, and pectin, among other active Sargassum components, were suggested to change blood low density lipoprotein (LDL)-cholesterol by preventing bile salts (Kumar, 2018). The high concentration of minerals, vitamins, long-chain fatty acids, essential amino acids, sterols, and fucoidans in S. wightii may also have positive benefits on broilers growth performance. The amount of Sargassum supplement added to the diet, the quality of the seaweeds utilised, and variations in the way seaweed meal is prepared (drying and particle size) can all affect how much broiler performance be improved.
Red Seaweeds
Red seaweeds offer significant nutritional qualities and are thought to be very pleasant to poultry and ruminant animals, including Chondrus crispus and Palmaria palmate. It has been demonstrated that dried red seaweeds, such as Polysiphonia sp., can provide growing broiler chicks with an intermediate supply of protein (up to 3%). As needed by poultry that is growing quickly. Polysiphonia sp. has higher quantities of minerals (32.4%) and proteins. On the other hand, inclusion had no appreciable impact on growth performance overall. Compared to calcium from limestone, calcium from calcified seaweeds can serve as an alternate source of dietary calcium, improving bone health and reducing lameness and weakness in the legs. The addition of the calcareous marine algae (CMA, at 0.45%, 0.6%, 0.75% and 0.9%) decreased feed intake and bird growth, which had a negative effect on bone strength because birds fed calcium (0.9%) from CMA had lower levels of phosphorus and ash in their tibiae. However, in birds fed 0.45% CMA, ileal calcium digestibility increased linearly (Walk et al., 2012). Lower concentrations of calcified seaweeds were found to increase phosphorous digestibility in broilers when dietary calcium from limestone was added in greater amounts (Bradbury et al., 2012). P. palmata (1.8%) was added to broiler diets, which raised body weight and improved serum IgA levels as well as the width, height, and surface area of ileal villus (Karimi, 2015). The body weight gain and feed intake were improved, and the HA titre and cell-mediated immunity (CMI) levels were raised when feed supplemented with Kappaphycus alvarezii (AF-KWP). Performance, immunity, and breast output in broiler chickens were all improved by adding 1.25% AF-KWP to their diet.
ANTIMICROBIAL EFFECT OF SEAWEEDS
Because the majority of the algal biomass in the lower GIT is not digested, seaweeds in poultry diets improve the gut microbiota and serve as substrates for bacterial fermentation. The metabolic activities of the beneficial microflora are altered by the prebiotic-like qualities of red and brown seaweeds, which also lower the prevalence of harmful bacteria. Additionally, a carbohydrate fraction from the red seaweed Gracilaria persica demonstrated direct anti-microbial effects against six bacterial pathogens, including Staphylococcus aureus, E. coli, Methicillin-resistant Staphylococcus aureus (MRSA), Salmonella typhimurium, Pseudomonas aeruginosa, and Aeromonas hydrophila, as well as induced a humoral-immunity. With regard to pathogenic, Gram-negative bacteria including E. coli, Klebsiella spp., and P. aeruginosa, water extracts of the red seaweeds Gelidium latifolium, Hypnea musciformis, Jania rubens, Jania spp., and Laurencia obtusa demonstrated strong in vitro anti-microbial properties (Alghazeer et al., 2013).
Seaweeds are continuously subjected to a variety of abiotic stimuli, including pathogenic microorganisms, desiccation, sunshine, osmotic stress, and severe temperatures. As a result, seaweeds have created defense mechanisms to withstand and survive these demanding circumstances. In addition to sulphated polysaccharides, organic acids, pigments, and phenolic compounds, they also create a variety of other special bioactive chemicals that have antiviral, antibacterial, and antioxidant properties. For instance, permeabilizing the bacterial cell wall and releasing the intracellular contents are two ways that phenolic chemicals demonstrate anti-microbial activity. Inhibiting food uptake, impairing protein and nucleic acid production, and disrupting electron transport chains are some other ways that phenolic chemicals fight bacteria.
Polysaccharides made from red seaweed also have anti-microbial properties because they have a preference for the bacterial surface appendages. The down-regulation of virulence factors, constrained motility, and reduced flagellar functions, as well as the direct inhibition of bacterial quorum sensing, have all been connected to the anti-microbial effects of red seaweeds and their extracted components on the poultry pathogen Salmonella enteritidis. In bacterial pathogens like Salmonella, quorum sensing molecules like auto-inducers (acylated homoserine lactones) have been found to promote virulence, motility, and biofilm formation. Previous research has demonstrated that some red seaweeds contain quorum sensing inhibitors, such as brominated furanones, which can prevent the formation of bacterial biofilms and the control of genes related to virulence and flagella, hence reducing bacterial growth (Janssens et al., 2008) .
Carrageenans and galactans from red seaweeds are examples of seaweed polysaccharides that target the viral attachment stages by either directly interacting with the virion or by simulating the binding of virus associated proteins (VAP) to the corresponding receptors (Hirayama et al.,2016). Additionally, during the internalisation and uncoating of the virus, marine polysaccharides can potentially prevent the allosteric processing of the viral capsid. For instance, carrageenans prevent viral attachment, internalisation, and uncoating; Ulva spp. prevented Newcastle disease virus fusion by preventing the cleavage of the intact protein F0 into the mature form; and fucoidans prevented viral infection by directly interacting with envelope glycoproteins (Elizondo-Gonzalez et al., 2012).
COMBINATION OF SEAWEEDS REQUIRES LOWER USE OF ANTIBIOTICS
Combination therapy may be used as a complementary approach to increasing the effectiveness of currently prescribed antibiotics. Such combination effects have been seen with a variety of anti-microbial peptides, compounds, plant extracts, and essential oils (Chovanova et al., 2015). Similar to this, seaweeds and antibiotics have been explored together to lengthen the effectiveness of vanishing (off-patent) antibiotics used in animal husbandry. The anti-microbial action of particular antibiotics, such as macrolides, beta-lactams, and tetracyclines, which are effective against pathogens like Pseudomonas, Acinetobacter, and Burkholderia spp., has been found to be enhanced by alginates from several brown seaweeds. Functional extracts from the red and brown seaweeds Gracilaria sp. and Porphyra dentata, as well as the brown seaweeds Laminaria japonica and Sargassum horneri increased the effectiveness of macrolides like clarithromycin against antibiotic-resistant E. coli. When combined with clarithromycin, ethanol extracts from several seaweeds have been found to synergistically suppress bacterial growth by impairing the action of efflux pumps. According to the postulated mechanism of action of the combined effect, quorum sensing in Salmonella was inhibited, which in turn suppressed the expression of genes linked to efflux, leading to an accumulation of tetracycline inside the bacterial cell and eventually to cell death.
PREBIOTIC PROPERTY OF SEA WEEDS
Prebiotics are a non-digestible food ingredient that affects the host by selectively stimulating the growth and/or activity of one, or a limited number of bacteria, in the colon. Prebiotics serve as preventative agents that can modify the gut microbiota to benefit the host and act as a barrier to pathogen colonization from the perspective of food safety. Prebiotics can have a direct or indirect impact on poultry, depending on whether they prime the host immune system or modify the composition and fermentation profile of the gastrointestinal microorganisms. These qualities make seaweeds and the bioactive substances they contain, like polysaccharides and phenolics, suitable as prebiotic dietary supplements with positive effects on gut health. By giving beneficial bacteria in broiler gut microbiota a substrate, prebiotics have been proven to promote digestive health in broiler. The majority of prebiotics work by one or more of the following mechanisms: creation of lactic acid, inhibition or prevention of pathogen colonization, alteration of the normal gut flora metabolic activity, and immune system stimulation (Reddy, 1999). The gut microbiome of chickens contains significant amounts of the helpful probiotic bacteria Bifidobacterium, Lactobacillus, Ruminococcus, and Streptococcus. These bacteria, which live in the small intestine, get their energy from fibres and non-digestible polysaccharides (Apajalahti, 2005).
CONCLUSION
Seaweeds vary in their nutrient composition according to species, season, environmental factors and feed processing methods. Hence, thorough analysis of their proximate composition is essential before inclusion in poultry diet. Seaweeds have multiple bioactive compounds and the bio-fucntional properties of these compounds should be exploited favorably to augment the productivity in broiler. Hence, combination of seaweeds as feed additive package can be used in broiler to enhance the productivity by considering economics of supplementation.
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