ANTI – NUTRITIONAL FACTORS

ANTI – NUTRITIONAL FACTORS

Waasifa Ansari – BVN20082, B.V.Sc., & A.H., Second professional year

Veterianry College and Research Institute, Namakkal.

TANUVAS, Chennai.

Poultry feed are routinely subjected to various contamination from diverse sources, including environmental pollution, activities of insects and microbes etc.Substances producing toxic deleterious effects that affectnormal nutrient metabolism of the species are known as anti – nutritional factors.ANF are chemical compounds synthesized naturally as secondary metabolites, reduce nutrient utilization, poor food intake and growth performance.

TYPE OF ANF

  Based on the type of nutrient affected and its biological response, ANF are classified as

• Depressants of nutrient digestion and metabolic utilization of proteins such as Tannins, Lectins, Saponins and Protease inhibitor.
• Diminishes solubility of mineral elements such as gossypol, oxalic acid, phytic acid and glucosinolakes.
• Inactivators of vitamin and hormones. Such as anti-vitamins and mimosines
• Moulds and Mycotoxins.
• Nitrate and Nitrite.
• DEPRESSANTS OF NUTRIENT DIGESTION AND METABOLIC UTILIZATION
• PROTEASE INHIBITORS

Inhibit proteolytic enzymes within GI tract commonly encountered ANF found in seeds of legumes. Especially soyabean has two types of inhibitors like kunitz inhibitor, a low disulphide bondcompound which specifically inhibit trypsin and bowman – brikinhibitor, a high disulphide bond compound which inhibits both trypsin and chymotrypsin.In commercial soybean meal the range of protease inhibitor is4 – 68 mg / g of protein.

Mode of Action

• Inhibit proteolytic activity of GI enzyme.

Consequence

• Raw soyabeanin chick feed produce pancreatic hyperplasia.
• It affect the protein digestibility of overall diet.
• The threshold of trypsin inhibitor activity of EuropeanUnionimport is 4.
• It is eliminated by addition of dietary antibiotics.
• TANNINS

It is coined by Seguin in 1796. It is a high molecular weight rich in phenyl hydroxyl groups provide effective cross links between proteins.

Two types of Tannins

• Hydrolysable tannin
• Condensed tannin

Mode of action

• Decreases protein digestibility by inhibiting enzymes and increasing faecal nitrogen, making protein unavailable.
• Inhibit the functions of Trypsin, Chymotrypsin amylase and lipase.
• Interferes with dietary iron absorption.

Consequences

• Decreases feed intake, growth rate, feed efficiency and protein digestibility.
• Increased Tannin leads to decreased enzyme action and decreased intestinal digestion
• SAPONINS

Perform soap like behaviour in aqueous solution commonly found in lucerne, white dover, red clover and soyabean.

Mode of Action

• Decreases uptake of glucose and cholesterol at gut via intra – luminal physio – chemical interaction.
• Hypo cholesterol emic effects.

Consequences           

• Decreases growth, feed efficiency, interferes with absorbtion.

Advantage:

• Antibacterial and antiprotozoal
• LECTINS (HAEMAGGLUTININ)
  Important group of ANF in both plant(soyabean, castor bean potatoes, banana, mangoes, wheat) and animal products (fish,eggs,snails,slugs, sponges)

Mode of action

• Clump or agglutinate RBC (Haemagglutinin)

Consequence

• Produce inflammatory reaction, edema and clotting of blood capillaries.

B.DIMINISHES SOLUBILITY OF MINERAL ELEMENTS

PHYTIC ACID

Available at a proportion of 1- 3 % by weight in all plant seeds and is a component of dietary fiber formed by combination of 6 phosphate molecules with inositol.

Mode of action

• Used as an antioxidant and strong chelalorof phosphate in vegetable oil and food additives.

Consequence

• Decreases abdominal fat in chicks.
• To reduce excretion of phosphorous, phytaseshas to be added.
• Pigs and chicken were able to convert phytic acid into available inorganic phosphorus, promoting the internal absorption of phosphoric acid.
• GLUCOSINOLATES

• Found in Cabbage, turnips, rapeseed and mustard seed.

Mode of action

• Decreases the synthesis of thyroid hormone, decreases the incorporation of iodine into the precursors of T₄ resulting in Goiter.

Consequences

• 15% 5 vinyl – oxazolidine-2- thiones in the diet of young chicks, depression of growth rate, hyperplasic and hypertrophy of thyroid gland.
• GOSSYPOL

Present in common protein source of poultry cotton seed meal.

Mode of action

• 2 naphthalene rings with restricted rotation produces mixture of enantiomers.

Consequences

• Decreased weight gain in broiler and poor feed efficiency.
• OXALATE

            Oxalic acid and strong bonds with Ca, Mg, Na, K.

Mode of Action

Oxalate makes strong bond with Ca, Na, K especially with Ca oxalate which decreasesCaabsorbtion resulted in hypocalcemia, secondary parathyroidism or osteodystrophyfibrosa.

 

INACTIVATORS OF VITAMIN AND HORMONES

• ANTI – VITAMIN A
• InRaw soyabean, the enzymelipoxygenasecatalyses the oxidation of carotene.
• Inclusion level 30 % of ground, raw soyabeancauses sharp lowering of Vitamin A and carotene in blood plasma.
• ANTI – VITAMIN D
• Raw soya protein producesrachitogenic activity in chick and pigs.
• ANTI – VITAMIN E
• Raw soyabean, kidney bean, alfalfa contain tocopheroloxidasewhich destroyVitamin E resulting in muscular dystrophy.
• Sweet clover hay decreases prothrombinlevel byinterfereing with blood clotting mechanism.

 

 

• METABOLIC TOXICANTS
• CYANOGENS
• Enzymatic hydrolysis releases
• Excess CNinhibits cytochrome oxidasewhich stops ATP formation.
• Death arrives due to tissue energy deprivation.
• NITRITES AND NITRATES

Mode of Action

Acute nitrate toxicity causes methamoglobinemia, cyanosis and death

Consequences

• Nitrate poisoning resulted with 90 – 100 mg / L in H₂O and3000 – 8000 mg / Kg in feed.
• In chickens and turkey increased NO₃¯ causes poor growth, anorexia, incoordination, hypovitaminosisA, rapid and labouredbreathing, frothing around mouth and death.
• MYCOTOXIN

Mycotoxins like aspergillus, fusarium, penicilliumhave adverse effects on health.

• AFLATOXICOSIS

Etiology

• Aflatoxin B1 (AFB1) – most common
• Aspergillusflavus and Aspergillusparasiticus causeshepatoxicity and nephrotoxicityin poultry
• LD₅₀ single dose of 0.3mg/kg b.wt(ducklings), 6 – 163mg/kg b.wt(chickens) causes immunosuppression, poor response to vaccine drop in egg production and poor hatchability.
• Aflatoxicosis causes histopathological lesions likehyperplasia of bile duct, degenerative and necrotic change in hepatocyte, nodular hyperplasia of liver parenchyma.

 

 

CITRININ TOXICOSIS

• It is produced byPencillumcitrinum resulted in endemic nephropathy.

Mode of Action

• Embryotoxic, immunotoxic, tetratoxic degenerative and necrotic changes in renal tubular epithelial cells, increase in size and weight of liver
• FUMONISINS TOXICOSIS
• It is produced by Fusariumventicilloides(corn)

Mode of action

• Increases intestinal fragility, swelling of kidney
• Decreases serum albumin,
• Mitochondrial abnormality.

Consequences:

• Hepatic necrosis and hepatocellular and biliary hyperplasia, Swollening of kidney, necrotic change in PCT
• Japanese quail chicks 200 ppm FB1 (21 d) resulted in formation of vesicular and tubular structure, in Endoplasmic Reticulum
• OCHRATOXICOSIS

Ochratoxin A produced by Aspergillusochraceus, Pencillumverrucosum

Mode of action

• Carcinogenic , embrytoxic , genotoxic , hepatoxic , immunotoxic, neprotoxic, neurotoxic, teratogenic

Consequences

• Poultry – nephropathy, anemia, decreases skeletal integrity impaired coagulation of blood, impaired phagocytosis and reduced growth rate
• TRICHOTHENES TOXICOSIS
• It is produced by Fusarium sp.
  • Causes Buccal oral ulcerations in young broiler chicks oral necrosis, affect body weight in growing chicks.
• MONILIFORMIN TOXICOSIS

It is produced byFusarium present in Corn, wheat, barley.

Mode of action

• Cardiotoxicity in chicks, poults, Japanese quails characterized by hypertrophic cardiomyopathy.
• Damaging effects of liver and kidney in poultry species.

METHODS TO REDUCE THE LEVEL OF ANTI – NUTRITIONAL SUBSTANCES IN FEED:

• Abundance of ANF and toxic influences in plants, present in feed stuffs, needs to be consisdered.
• Nutritional quality can be improved by removal of undesirable components.
• Effective methods like simple and inexpensive can be practiced byprocessing techniques.
• For tannin physical methods like wilting, processing, ensiling, inoculation with tannin resistant bacteria and chemical techniques treatment with alkalis, organic solvent, precipitants etc., can be used.
• Use of polyethylene glycol for which tannins have higher affinity than for proteins is by far the most used reagent to neutralize these secondary compounds.
• Lower level of phytic acid (24.7% loss) can be achived by longer time of boiling, microwave and autoclaving.
• Roasting can also help in reduction of phytic acid.
• Trypsin inhibitor activities can be completely inactivated by boiling (40 minutes) and autoclaving (20 minutes).
• Cyanide content of Moringaoleifera leaves by boiling, shimmering and blanching is reduced by 88.10% , 80.95% , 61.91% respectively .
• Electron beam radiation (9.33 KGy) reduced hydrocyanic acid, phytic acid and tannic acid to the extent of 34, 63, 22 per cent respectively.
• Dehulling after germination reduces tannin and phytic acid by 43 – 52 percent and 47 – 52 percent respectively.
• Among various processing methods Soaking was found to reduce the ANF levels.

CONCLUSIONS

Anti – nutrient present in plant protein sources is a major constraint for its potential utilization in livestock feeding.

Bioavailability of nutrients, concentration type and nature nutrients, given to the animal is necessary to assess the overall nutritional potential value of any plant protein source.

• Appropriate and effective processing techniques have to be employed to reduce the adverse effects of ANF in plant protein sources and to improve its nutritive value.
• Concentration of ANF directly proportional to species of plants and post-harvest treatments.
• Feed supplements like amino acids, vitamins, minerals help in neutralization of ANF present in feed stuff.
• Germination along with dehulling process improved the quality of legumes by increasing the bioavailability and digestibility of nutrients and also it reducing ANF.
• Results from this study, suggested electron beam (9.33 KGy ) reduced tannin, phytic acid and hydrocyanic acid from unconventional aqua feed ingredients. It has an upper hand against conventional methods in reduction of anti – nutrients.

 

Keywords:

ANF, Tannins, Saponins, Glucosinolates, Gossypol, Mycotoxins, Anti-vitamins, Nitrites and nitrates, Oxalates, Electron beam.