L ‐canavanine: A natural feed‐intake inhibitor for pigs (isolation, identification and significance)

Abstract : A major feed‐intake inhibitor for pigs is present in seeds of Vicia villosa spp dasycarpa Roth cv Namoi. When the seed is fed for 4 days at only 80 g kg −1 of the diet, it produces a steady diminution in daily feed intake to 25% or less of their pre‐treatment consumption ( P < 0·001), after the first feeding. The inhibitor has been isolated and identified as L ‐canavanine. When analytically pure L ‐canavanine dihydrochloride is supplied at an equivalent dietary concentration (13·0 mmol kg −1 ) to that supplied by 80 g kg −1 of Namoi vetch seed, it successfully mimics the response. The response is only observed after the first meal. A review of published literature showed the diversity of animal species exhibiting a feed‐inhibition response to canavanine‐containing seeds. These reports suggest that this well‐documented arginine analogue will be a useful molecule for the study of post‐ingestion feed‐intake regulation. An ambient temperature procedure for the large‐scale isolation of L ‐canavanine dihydrochloride is described.