Original scientific paper
CHANGES IN DIGESTIBILITY AND BIOLOGICAL VALUE OF PUMPKIN SEED CAKE PROTEIN AFTER LIMITING AMINO ACIDS SUPPLEMENTATION
Tatjana Pirman
; Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia
Maja Marič
; Kardeljev trg 9, Velenje, Slovenia
Andrej Orešnik
; Biotechnical Faculty, University of Ljubljana, Domžale, Slovenia
Abstract
Pumpkin seed cake is a by-product in the production of a very tasty and special quality pumpkin oil. The amount of crude protein in the analysed pumpkin seed cake sample was 520.2 g in the dry matter. Lysine and methionine are the first and the second limiting amino acids in pumpkin seed cake proteins. The effect of one or two limiting amino acids addition into the test diet on the digestibility and
biological value of pumpkin seed cake protein was determined in the experiment on laboratory rats. 16 young male Wistar laboratory rats (4 per group) were housed in individual balance cages and fed ad libitum either control (C) diet, or diet with added lysine (L), or methionine (M), or both amino acids (L+M). During the time of experiment the amount of consumed diet and the body weight of animals were registered. There was no significant difference in the consumed amounts of the diets between the control and experimental groups. The apparent and true digestibilities of protein were similar in all groups, in average 88.47 % and 93.69 %, respectively. Protein biological value (56.62, 59.71, 58.78 and 61.68) and net protein utilisation (53.10, 56.33, 55.01 and 57.38) were increased after the addition of amino acids into the diet. The most pronounced and statistically significant (P <0.05) difference was obtained after the jointly addition of lysine and methionine. Protein efficiency ratio (PER) was increased from 1.53 g in the control group to 1.75 g, 1.70 g and 2.12 g in L, M and L+M groups respectively, but statistically significant (P < 0.05) only in L+M group. Also laboratory rats growth rate and efficiency of consumed diet were significantly (P < 0.05) increased in the diet supplemented with two amino acids together (L+M), but not in other two experimental diets. After additional limiting amino acids feeding, the amount of excreted N (mg/g of gain) was reduced from 38.97 mg in control group to 24.43 mg (P < 0.05) in L+M group.
Keywords
nutrition; laboratory rats; pumpkin seed cake; digestibility; protein biological value; amino acids
Hrčak ID:
26510
URI
Publication date:
30.4.2007.
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