Adverse effects of dietary lupine in broiler chickens

This study describes the adverse effects of dietary lupines in broiler chic kens for which lupine seeds (Lupinus angustifolius) in raw, dehulled, or au toclaved forms were used as a replacement for soybean meal (SBM) in practic al diets. Test diets contained 35% SBM (control) or raw (40%), autoclaved ( 40%), or dehulled (35%) lupine seed meal. All diets were isocaloric (3,230 kcal/kg AME) and isonitrogenous (23% crude protein). Each diet was offered ad libitum to a group of 16 (four replicates with four birds per replicate) day-old male broiler chicks for 21 d. Chemical analysis of lupine seeds sh owed no detectable levels of mycotoxins, and total alkaloid contents were b elow 0.01%. Decreased food intake and growth rate were the main signs obser ved in all birds fed lupine-based diets. These adverse effects were observe d during the first week and persisted throughout the trial. Acute signs of toxicity were observed in four chicks fed the diet containing raw lupine se ed during the first week of exposure. Initial clinical signs included leg w eakness, lack of coordination, and torticollis. In later stages, during Wee ks 2 and 3, some birds fed lupine-based diets showed signs of muscle paraly sis and skeletal deformity. Postmortem examination did not show gross patho logical changes associated with the dietary treatments. Liver microsomal cy tochrome P-50 content was higher (P < 0.05) in birds fed the raw lupine-bas ed diet (mean 0.56 pmol/mg protein) in comparison with controls (mean 0.25 pmol/mg protein), which indicated a systemic effect. Based on the present r esults, it can be stated that high levels of some varieties of sweet lupine s in broiler diets may cause significant adverse effects manifested as 1) d ecreased feed intake and growth rate in most of the birds, and 2) specific signs of acute and chronic toxicity in some individuals.