Nutritive value and non-toxicity of Botryosphaeria zeae-infected wheat for weaner pigs
A novel fungal infection of wheat by Botryosphaeria zeae was identified on the Darling Downs of Queensland, Australia and called ‘white grain’ because of its bleached appearance. The only nutritional changes in the wheat grain infected with B. zeae were decreases in nitrogen and total amino acids (∼5%), and slight increases in the lysine, fibre and fat content, with starch unaffected. Nutrient digestibility and potential toxicity were assessed in weaner pigs housed in metabolism crates and fed this grain over a 4-week period, as they grew from 15 to 35 kg. Digestibility of energy and nitrogen in white grain was not different from that of normal wheat. The piglets were then bled for biochemical and haematological testing, slaughtered and the entire viscera subjected to gross pathological inspection, followed by histological examination of the liver, kidney, pancreas, spleen, heart, lung, muscle and intestine. White grain did not affect palatability of diets, pig growth rates; no abnormalities were detected in tissues, while biochemical and haematological parameters did not suggest any toxic effect. Hence, wheat with white grain appears suitable for use in pig diets, but the use of this wheat for human food should be restricted until additional longer term studies are conducted.