UEDA Hiroshi School of Agriculture, Kagawa University, 農学部, 助教授 (30116884)
HORIGOME Takao School of Agriculture, Okayama University, 農学部, 教授 (00040824)
OKUMURA Jun-ichi School of Agriculture, Nagoya University, 農学部, 助教授 (10023425)
OHSHIMA Mitsuaki School of Agriculture, Nagoya University, 農学部, 助教授 (20035976)
KAYAMA Ryosei School of Agriculture, Nagoya University, 農学部, 教授 (10031163)
Legumes and forage grasses contain large amounts of protein, most of which may not be utilized efficiently by ruminants when given in the diet. An attempt was made, therefore, to extract excessive amounts of leaf protein and use the leaf protein concentrate more efficiently as a source of dietary protein for single-stomached animals. For this purpose, it is necessary to press juice from crushed grass followed by the precipitation of protein in the juice and drying the precipitated protein.
By comparing the precipitation methods, it was found that fermentation treatment caused a low recovery and inferior quality whereas high recovery was attained by alkali treatment, i. e. adjusting pH to 8 prior to heating. Heat-drying treatment of the precipitated protein led to the decomposition of amino acids, especially lysine. The mineral composition of the leaf protein concentrate was very different from that of an ordinary animal feed and was not well balanced for animal growth. By balancing the mineral composition, however, the utilization of the leaf protein concentrate was improved. Particularly notable was a high saponine content of the leaf protein concentrate extracted from alfalfa. When a large amount of saponine was included in the diet, chicks had severe growth retardation, which was completely counteracted by supplementing the diet with cholesterol at the same amount as saponine.
Besides these basic studies, a few practical experiments were also conducted. Without causing a detrimental effect on egg production, the leaf protein concentrate could be substituted for soybean meal in the diet for laying hens up to 5% on a protein basis, and even the supplementation was useful for gaining more yellowish color in the yolk. The leaf protein concentrate could be used as a protein source for the pigling diet at various amounts depending on the age.