Camp. Biochem.Physiol.Vol. IOIA, No. 3, pp. 613-618, Printed in Great Britain
1992 0
0300-%29/92 WI0 + 0.00 1992 Pergamon Press plc
EFFECTS OF VARIOUS FAT SOURCES ON GROWTH AND HEPATIC MITOCHONDRIAL FUNCTION IN MICE MASAAKI TOYOMIZU,* KAZUKO MEHARA,TETSUROKAMADA~and YUICIIIROTOMITA Animal Nutrition, Department of Animal Science, Kagoshima University, Korimoto, Kagoshima, Japan 890; TDepartment of Laboratory Medicine, Faculty of Medicine, Kagoshima University, Sakuragaoka, Kagoshima, Japan 890 (Received 5 July 1991) Abstract-l. Five parameters with biophysical meaning for Parks’ feeding and growth equations showed that mice fed diets containing hydrogenated beef tallow or beef tallow had lower mature body weight than soybean oil, linseed oil or fish oil-fed groups, and that mice fed hydrogenated beef tallow or fish oil diets had a lower feed efficiency factor than beef tallow, soybean oil or linseed oil-fed groups. 2. Mice fed the diet containing soybean oil or linseed oil had higher carcass fat as a per cent of body weight, significantly different from mice. fed hydrogenated beef tallow, which exhibited the lowest carcass fat. 3. The respiratory rate of state 3 and the rate of ATP synthesis of liver mitochondria isolated were highest in the group fed the diet containing soybean oil.
INTRODUCTION
utilization of mice.
Many biological responses to dietary fat sources have been investigated: for example, the effects of the type of dietary fat or essential fatty acid deficiency on rat pancreatic lipase (Sabb et al., 1986); oxidative phosphorylation and fatty acid of rat liver mitochondria (Stancliff et al., 1969; Divakaran and Venkataraman, 1977; Rafael et al., 1984); plasma lipoprotein composition in rats (Ney et al., 1982); lipid composition and properties of liver microsomal membrane of rats (Christon et al., 1988; Field et al., 1989); epidermal lipoxygenase products in guinea pigs (Miller et al., 1990) and thermogenic activity of brown adipose tissue in mice (Mercer and Trayhurn, 1987). However, as far as dietary fat sources are concerned, few responses of food intake and body weight have been described as a function of age, and many studies to date have been restricted to relatively short-term experiments. Therefore, the characteristic effects of dietary fat sources on these parameters are not yet obvious. Parks (1982) developed two equations containing biologically significant parameters for describing the growth and ad lib. feeding of animals as input-output devices. Recently, the authors demonstrated how dietary protein level and fat level influenced gross energy intake and body weight of mice from weaning to maturity (Toyomizu et al., 1988, 1991). The present work was undertaken to determine the relatively long-term effects of dietary fat on the feeding and growth patterns of mice fed diets containing hydrogenated beef tallow, beef tallow, soybean oil, linseed oil and fish oil. A further objective was to compare the effects of the diets containing various fats on body composition and the efficiency of energy
at the level of the mitochondrion
in liver
MATERIALSAND METHODS Animals and diets The mice used in this study are a Y race developed in Japan from a German genotype designated as dd. Forty ddY male mice (Kyudo Co. Ltd, Kumamoto), 21 days old, weighing 8.1 f 0.6 g, were distributed into five groups of eight mice. each, with the body weights as uniform as possible. They were housed individually in wire cages under controlled light (12 hr light: 12 hr dark) and temperature (24 + 1°C). Animals were fed for 72 days with nurified diets supplemented with 8.7% (wt/wt) fat- providing different fatty acid combinations (Table I), and diets were named hydrogenated beef tallow, beef tallow, soybean oil, linseed oil and fish oil. The fatty acid composition of each oil is summarized in Table 2. All diets except fish oil were prepared every 5 weeks and stored at - 20°C while fish oil was
*Present address: Animal Nutrition, Faculty of Agriculture, Niigata University, 2-8050 Ikarashi, Niigata, Japan 950-2 1, Telephone: 25-262-66 13; Fax: 25263- 1659. 613
Table 1. Composition Oilt Casein a-Cornstarch Glucose
CdlUlOSe Choline Mineral1 Vitamin5 Total
of the basal diet* 8.70 24.32 18.82 37.63 4.19 0.21 5.24 0.89 100.00
+Casein, glucose, a-cornstarch and cellulose powder were purchased from Oriental Yeast Co., Tokyo. tThe oils added were: hydrogenated beef tallow, beef tallow, soybean oil, linseed oil and fish oil. Those except soybean oil were obtained from Katayama Chemical Industries Co. Soybean oil was obtained from Nacalai Tesque, Inc., Kyoto, Japan. SSee Rogers and Harper (1965). 9.8~6 of Na, SeOJ was added to 1g of the mixture. Qee Harper (1959).
614
MASAAKITOYOMIZU et al. Table 2. Fatty acid comwsitioo Hydrogenated beef tallow
of the exuerimental
Beef
Soybean oil
tdlOW
Fattv acid c14:o C16:O Cl6:l c17:o C18:O C18:I C18:2uJ6 Cl8:303 c2o:o C20:109 C20:3 C20:4w6 C20:503 C22:l C22:4 C22:6w3 C24: I
diets
Linseed oil
Measurement of mitochondrial respiration
Fish oil
P/01 8.9 36.5 0.7 1.6 44.0 8.0 0.4
4.8 26.2 3.6 1.2 18.4 40.2 2.6 -
-
0.5 11.6 -
;6 -
3.2 22.5 55.9 5.1 0.6 -
2.7 19.3 14.5 56.7 1.2 -
-
-
-
1.9 15.6 8.2 0.9 2.2 20.2 1.3 10.2 3.0 8.5 0.8 11.5 3.1 0.5 5.8
prepared every 4 days and stored under the same condition. Food and water were supplied ad lib. The carbohydrate source was a 1: 2 (by wt) mixture of c -cornstarch and glucose. The protein source was casein [crude protein (CP) 83.9%]. Individual body weight and food intake were recorded every 4 days. Food intake and growth cuwes Each group of data was analysed to obtain values of the five parameters C, r, D, A and (AB) in the feeding and growth equations (1) and (2), proposed by Parks (1982) namely dF/dt =(C-D)[l
-exp(-t/r)]+D,
W(t) = (A - W,)[l - exp(-AB)F(r)/A]
(1)
+ W,,
(2)
here dF/dt = instantaneous food intake (g/day) at time t, C = mature food intake (g/day), t = time (days) after weaning, D = initial food intake (g/day), r = exponential decay constant of instantaneous food intake (days), W(t) = body weight at time t (g), A = mature body weight (g), IV, = initial body weight (g) at weaning, (AB) = feed efficiency factor (g body weight/g food intake) and F(t) = cumulative food consumed at time t (g). Equation (1) was integrated with respect to time (t) to obtain cumulative food consumed, F(t), from which cumulative food intake, f(t), for the t-th 4 day period was found by, f(t) = F(t) - F(t - 4) =4C+r(C-D)exp(-t/r)[l-exp(4/5)].
(3)
To minimize the accumulation of errors in observed cumulative food consumed, F(t), equation (2) was rewritten as
W(t) = [A - W’(t - 4)](1 - exp[-(AB)f + W(t - 4),
(t)/A]) (4)
where W(t - 4) = body weight at the previous weighing (g), f(t) = food intake for 4 days and initial W, = 8.1. - ‘The parameters in equations (3) and (4) “were estimated from data of every cumulative food intake for the 4 day period and body weight of mice within each group using a nonlinear regression program (Statistical Analysis Systems Institute, 1979), which utilizes the Marquardt method of iteration. The initial estimate of D is f(l)/4. The logtransformed data were fitted to the logs of equations (3) and (4) to make the variance largely independent of the mean.
Eight mice for each group were killed by cervical dislocation at a feeding duration of 73-16 days and livers immediately excised. Liver mitochondrial isolation was performed according to the modified method of Johnson and Lardy (1967). Briefly, a 10% homogenate was prepared in cold buffer containing 250 mM sucrose. 10 mM Tris-HCl @H 7.4) and nuclei aid cell debris removed by centrifugation at 600g for 10 min; mitochondria were pelleted by centrifugation at 5000 g for 20 min, then washed twice by centrifugation at 55006 for 15 min. Bates of oxygen utilixation were measured with 10 mM pyruvate and 2.5 mM malate as substrates, in the following reaction mixture (pH 7.0): 80mM KCI, 50mM Mops,
1992 0
0300-%29/92 WI0 + 0.00 1992 Pergamon Press plc
EFFECTS OF VARIOUS FAT SOURCES ON GROWTH AND HEPATIC MITOCHONDRIAL FUNCTION IN MICE MASAAKI TOYOMIZU,* KAZUKO MEHARA,TETSUROKAMADA~and YUICIIIROTOMITA Animal Nutrition, Department of Animal Science, Kagoshima University, Korimoto, Kagoshima, Japan 890; TDepartment of Laboratory Medicine, Faculty of Medicine, Kagoshima University, Sakuragaoka, Kagoshima, Japan 890 (Received 5 July 1991) Abstract-l. Five parameters with biophysical meaning for Parks’ feeding and growth equations showed that mice fed diets containing hydrogenated beef tallow or beef tallow had lower mature body weight than soybean oil, linseed oil or fish oil-fed groups, and that mice fed hydrogenated beef tallow or fish oil diets had a lower feed efficiency factor than beef tallow, soybean oil or linseed oil-fed groups. 2. Mice fed the diet containing soybean oil or linseed oil had higher carcass fat as a per cent of body weight, significantly different from mice. fed hydrogenated beef tallow, which exhibited the lowest carcass fat. 3. The respiratory rate of state 3 and the rate of ATP synthesis of liver mitochondria isolated were highest in the group fed the diet containing soybean oil.
INTRODUCTION
utilization of mice.
Many biological responses to dietary fat sources have been investigated: for example, the effects of the type of dietary fat or essential fatty acid deficiency on rat pancreatic lipase (Sabb et al., 1986); oxidative phosphorylation and fatty acid of rat liver mitochondria (Stancliff et al., 1969; Divakaran and Venkataraman, 1977; Rafael et al., 1984); plasma lipoprotein composition in rats (Ney et al., 1982); lipid composition and properties of liver microsomal membrane of rats (Christon et al., 1988; Field et al., 1989); epidermal lipoxygenase products in guinea pigs (Miller et al., 1990) and thermogenic activity of brown adipose tissue in mice (Mercer and Trayhurn, 1987). However, as far as dietary fat sources are concerned, few responses of food intake and body weight have been described as a function of age, and many studies to date have been restricted to relatively short-term experiments. Therefore, the characteristic effects of dietary fat sources on these parameters are not yet obvious. Parks (1982) developed two equations containing biologically significant parameters for describing the growth and ad lib. feeding of animals as input-output devices. Recently, the authors demonstrated how dietary protein level and fat level influenced gross energy intake and body weight of mice from weaning to maturity (Toyomizu et al., 1988, 1991). The present work was undertaken to determine the relatively long-term effects of dietary fat on the feeding and growth patterns of mice fed diets containing hydrogenated beef tallow, beef tallow, soybean oil, linseed oil and fish oil. A further objective was to compare the effects of the diets containing various fats on body composition and the efficiency of energy
at the level of the mitochondrion
in liver
MATERIALSAND METHODS Animals and diets The mice used in this study are a Y race developed in Japan from a German genotype designated as dd. Forty ddY male mice (Kyudo Co. Ltd, Kumamoto), 21 days old, weighing 8.1 f 0.6 g, were distributed into five groups of eight mice. each, with the body weights as uniform as possible. They were housed individually in wire cages under controlled light (12 hr light: 12 hr dark) and temperature (24 + 1°C). Animals were fed for 72 days with nurified diets supplemented with 8.7% (wt/wt) fat- providing different fatty acid combinations (Table I), and diets were named hydrogenated beef tallow, beef tallow, soybean oil, linseed oil and fish oil. The fatty acid composition of each oil is summarized in Table 2. All diets except fish oil were prepared every 5 weeks and stored at - 20°C while fish oil was
*Present address: Animal Nutrition, Faculty of Agriculture, Niigata University, 2-8050 Ikarashi, Niigata, Japan 950-2 1, Telephone: 25-262-66 13; Fax: 25263- 1659. 613
Table 1. Composition Oilt Casein a-Cornstarch Glucose
CdlUlOSe Choline Mineral1 Vitamin5 Total
of the basal diet* 8.70 24.32 18.82 37.63 4.19 0.21 5.24 0.89 100.00
+Casein, glucose, a-cornstarch and cellulose powder were purchased from Oriental Yeast Co., Tokyo. tThe oils added were: hydrogenated beef tallow, beef tallow, soybean oil, linseed oil and fish oil. Those except soybean oil were obtained from Katayama Chemical Industries Co. Soybean oil was obtained from Nacalai Tesque, Inc., Kyoto, Japan. SSee Rogers and Harper (1965). 9.8~6 of Na, SeOJ was added to 1g of the mixture. Qee Harper (1959).
614
MASAAKITOYOMIZU et al. Table 2. Fatty acid comwsitioo Hydrogenated beef tallow
of the exuerimental
Beef
Soybean oil
tdlOW
Fattv acid c14:o C16:O Cl6:l c17:o C18:O C18:I C18:2uJ6 Cl8:303 c2o:o C20:109 C20:3 C20:4w6 C20:503 C22:l C22:4 C22:6w3 C24: I
diets
Linseed oil
Measurement of mitochondrial respiration
Fish oil
P/01 8.9 36.5 0.7 1.6 44.0 8.0 0.4
4.8 26.2 3.6 1.2 18.4 40.2 2.6 -
-
0.5 11.6 -
;6 -
3.2 22.5 55.9 5.1 0.6 -
2.7 19.3 14.5 56.7 1.2 -
-
-
-
1.9 15.6 8.2 0.9 2.2 20.2 1.3 10.2 3.0 8.5 0.8 11.5 3.1 0.5 5.8
prepared every 4 days and stored under the same condition. Food and water were supplied ad lib. The carbohydrate source was a 1: 2 (by wt) mixture of c -cornstarch and glucose. The protein source was casein [crude protein (CP) 83.9%]. Individual body weight and food intake were recorded every 4 days. Food intake and growth cuwes Each group of data was analysed to obtain values of the five parameters C, r, D, A and (AB) in the feeding and growth equations (1) and (2), proposed by Parks (1982) namely dF/dt =(C-D)[l
-exp(-t/r)]+D,
W(t) = (A - W,)[l - exp(-AB)F(r)/A]
(1)
+ W,,
(2)
here dF/dt = instantaneous food intake (g/day) at time t, C = mature food intake (g/day), t = time (days) after weaning, D = initial food intake (g/day), r = exponential decay constant of instantaneous food intake (days), W(t) = body weight at time t (g), A = mature body weight (g), IV, = initial body weight (g) at weaning, (AB) = feed efficiency factor (g body weight/g food intake) and F(t) = cumulative food consumed at time t (g). Equation (1) was integrated with respect to time (t) to obtain cumulative food consumed, F(t), from which cumulative food intake, f(t), for the t-th 4 day period was found by, f(t) = F(t) - F(t - 4) =4C+r(C-D)exp(-t/r)[l-exp(4/5)].
(3)
To minimize the accumulation of errors in observed cumulative food consumed, F(t), equation (2) was rewritten as
W(t) = [A - W’(t - 4)](1 - exp[-(AB)f + W(t - 4),
(t)/A]) (4)
where W(t - 4) = body weight at the previous weighing (g), f(t) = food intake for 4 days and initial W, = 8.1. - ‘The parameters in equations (3) and (4) “were estimated from data of every cumulative food intake for the 4 day period and body weight of mice within each group using a nonlinear regression program (Statistical Analysis Systems Institute, 1979), which utilizes the Marquardt method of iteration. The initial estimate of D is f(l)/4. The logtransformed data were fitted to the logs of equations (3) and (4) to make the variance largely independent of the mean.
Eight mice for each group were killed by cervical dislocation at a feeding duration of 73-16 days and livers immediately excised. Liver mitochondrial isolation was performed according to the modified method of Johnson and Lardy (1967). Briefly, a 10% homogenate was prepared in cold buffer containing 250 mM sucrose. 10 mM Tris-HCl @H 7.4) and nuclei aid cell debris removed by centrifugation at 600g for 10 min; mitochondria were pelleted by centrifugation at 5000 g for 20 min, then washed twice by centrifugation at 55006 for 15 min. Bates of oxygen utilixation were measured with 10 mM pyruvate and 2.5 mM malate as substrates, in the following reaction mixture (pH 7.0): 80mM KCI, 50mM Mops,
