**4.9 Nutritional management, gastro-intestinal tract conditioning and poultry health**

It's undeniable fact that achievement of productive efficiency can only be attained through nutrition if and only if the health status of birds is not compromised. Therefore, current nutritional researches are geared towards optimising poultry health and consequently their welfare. Some of these nutritional strategies with positive impact on poultry welfare have been reviewed extensively [58]. They include: manipulation of diet composition (e.g. dietary ME/CP as a way of controlling the body composition to prevent body fatness of market broilers or fatty liver haemorrhagic syndrome in layers); addition of essential fatty acids such as linoleic acid and linolenic acid to prevent lesions or supplemental fats/oils to increase dietary ME values; use of calcium and phosphorus (an approximate ratio of 2: 1), or vitamin D to prevent bone problems such rickets and tibial dyschondroplasia or cartilage abnormalities that can lead to welfare problems such as osteomyelitis and femoral head necrosis; use of major supplemental mineral like sodium/vitamin and trace mineral supplements to boost normal health and/or under adverse conditions; use of feed additives such as enzymes and probiotics discussed above (Section 4.5) to improve feed efficiency with added advantage of less sticky excreta (better litter quality with less incidence of hock burns) and control of disease causing organisms, respectively; dietary modifications to help birds cope with stress, particularly under hot climatic conditions (e.g. decreasing crude protein content, use of synthetic amino acids to increase amino acid intake, use of fat to help decrease heat increment, use of sodium supplement as bicarbonate for maintenance of blood electrolyte balance, use of vitamins such as vitamins C, E and A to help in heat and other types of stress); and physical manipulation of feed such as mash feeding and feed restriction to control growth for maintenance of good health (e.g. lower mortality, reduction in metabolic disorders, improved walking ability).
