Antinutritional factors

Antinutritional factors

1. Antinutritional factors

2. Antinutritional factors Substances which either by themselves or through their metabolic products, interfere with food utilization Affect the health and production of animals

3. Characteristics Secondary Products of metabolism Found in virtually all plants to some degree. Common in tropical forages.

4. Charcteristics Bitter Colored Poisonous Odor Antinutritive Immunosuppresive

5. Common Antinutritional factors Protease inhibitors Lipase Inhibitors Glycosides Saponins Alkaloids Phytic acid Tannins

6. Protease Inhibitors Inhibit the actions of Trypsin Pepsin Other proteases

7. Protease Inhibitors In the gut,they prevent the Digestion of protein Absorption of protein For example Bowman- Birk trypsin inhibitor is found in soybeans.

8. Lipase Inhibitors Interfere with enzymes, such as Pancreatic lipase, that catalyze the hydrolysis of some lipids, including fats. For example, Anti-obesity drug orlistat causes a percentage of fat to pass through the digestive tract undigested.

9. Glycosides Generally bitter Structure Contain CHO and non-CHO groups( aglycone ) Mode of action Toxicity results from aglycone release during enzymatic degradation Sources Linseed, sorghum, soyabean , clover etc

10. Saponins Have distinctive foaming characteristics Present in White clover Alfalfa Brachiaria decumbens etc.

11. Effects of Saponins Bloat Haemolysis GIT erosion Inhibit enzyme action

12. Alkaloids Basic in nature Toxic For example Cocaine Nicotine Caffeine

13. Effects of alkaloids It can cause Kidney damage Pulmonary damage Liver damage Diarrhea

14. Phytic acid It has a strong binding affinity to minerals such as calcium, magnesium, iron, copper, and zinc. It makes the minerals unavailable for absorption in the intestine. Phytate has direct anti-nutritional effects for poultry causing reductions in performance by lowering amino acid and mineral absorption.

15. Tannins Compounds that tan leather Polyphenolic compounds that can form stable complexes with: Proteins Carbohydrates Minerals Have beneficial/harmful effects

16. Selected Forage Plants with Tannins Lotus species Sainfoin Faba beans Peas Sorghum Calliandra calothyrsus Leucaena leucocephala Sesbania sesban Gliricidia sepium Acacia species

17. PAs affect forage utilization by: Forming strong H bonds with other nutrients. Inhibition of digestive enzymes. Inhibition of rumen microbial activity. Concentrations >7% usually reduce nutrient utilization.

18. Effect of PAs on forage quality Positive effects Increased efficiency of protein utilization. Reduction of parasite burden. Reduction of proteolysis. Bloat prevention. Increase quality of animal products. Reduction of N emission into the environment.

19. Effect of PAs on forage quality Negative effects Reduction in digestibility Erosion of GIT lining Toxicity

20. References D’Mello,JPF2000.Farm animal metabolism and nutrition. (Ed.). CAB, Wallingford. P319. Chapter 18Caygill, J C and Mueller-Harvey 1999. Secondary plant products. Nottingham University press. Cheeke , P R and Shull L R 1998. Natural toxicants in feeds and poisonous plants. AVI Publ. Co. Garland T and Barr, C. 1998. Toxic plants and natural toxicants. CAB International