Effects of feeds containing different fats on carcass and blood parameters of broilers
Effects of diets containing fats on some carcass characteristics and blood parameters of broilers were investigated. Broilers were fed one of four different isonitrogenous diets containing 6% added fat. The effect of different fat sources on the moisture, ash, and fat ratios of thigh and breast of broilers was statistically significant. The effect of different fats on serum cholesterol, high-density lipoproteins (HDL), and low-density lipoproteins (LDL) in broilers of broilers was significant, but the effect of those on triglyceride values was not significant. The effect of sex on blood parameters for cholesterol and triglyceride values was not statistically significant. However, the HDL value of males and the LDL value of females were significantly different.
Key words: oil, tallow, feed, carcass, blood, broiler
DESCRIPTION OF PROBLEM
There have been numerous reports on the effects of added fats in poultry diets. Although the effects of fats and vegetable oils have been examined on diet quality and performance of animals in the previous studies, today, direct or indirect effects of fats on animal and human health are being determined. On the basis of the previous results, the effects of fats and vegetable oils need to be examined not only for production characteristics but also for meat quality and blood parameters relative to human health. When fat-related studies on chicken are scrutinized, it is found that the fats and vegetable oils according to their energy and fatty acid characteristics affect the production [1, 2, 3, 4, 5], meat quality [6, 7, 8, 9], and blood characteristics of broilers [10, 11, 12]. When the studies were examined regarding the physiology and fat metabolism of chickens, it was shown that cholesterol values in the blood and tissue of males were higher than those of females [10, 13, 14]. It has also been reported that cholesterol in blood and tissue of broilers and rats increases with age [15, 16]. In other studies on feeding with different fat sources of broiler, it has been shown that the amount of abdominal fat in female broilers is higher than that of males [13, 17, 18].
MATERIALS AND METHODS
Three hundred sixty male and female 1-dold broiler chicks (Ross strain) were used. The birds were individually wing-banded, weighed, and placed randomly in 12 floor pens (15 male and 15 female chicks per pen). There were four dietary treatments with three replicates (pens) each. The experimental treatments were formulated to meet NRC  recommendations for all nutrients. Analyses of metabolizable energy were made using procedures of the Association of Official Analytical Chemists . The diets consisted of 6% added fat from four sources and were formulated to be isonitrogenous (Table 1). The fats used included sunflower oil (SFO), corn oil (CO), soybean oil (SO), and tallow (T). All chicks were fed with starter diets up to 21 d and then were fed with finisher diets from 22 to 42 d. The diets were fed ad libitum. Water was provided by nipple drinkers.
Prior to slaughter, broilers were given a feed withdrawal period of 12 h to decrease the effects of feeding on blood parameters of the chicken. Before slaughter, two male and two female chickens were randomly selected from one replicate for each of the four treatments for blood sampling and carcass analysis. Blood samples were obtained from each bird by jugular vein puncture and drawn into vacuumed capillary tubes in order to determine the blood cholesterol, triglyceride, high-density lipoprotein (HDL), and low-density lipoprotein (LDL) levels. After coagulation, blood samples were centrifuged at 2,000 rpm, and then serum was collected and stored at -20[degrees]C for later analysis. Blood cholesterol, triglyceride, HDL, and LDL levels were determined spectrophotometrically  by using commercial kits . Blood parameter values were expressed as milligrams per 100 mL.
After blood processing, four broilers were slaughtered, defeathered, processed (removal of head and feet), and eviscerated (removal of gastrointestinal tract). Carcasses were stored at 4[degrees]C for about 16 h. Afterward, the carcasses were dissected, and samples from the different portions were collected: breast meat plus attached skin, thigh muscles plus attached skin. Meat samples were homogenized using a blender with horizontal blades, and samples were frozen and stored in a freezer at -20[degrees]C until further analyses. Chemical analyses for moisture, protein, and ash were performed on all meat samples. Fat was extracted with ethyl ether using a Soxhelet apparatus .
Analysis of variance of the data was conducted by using pen means. Differences among treatments were determined with Duncan’s multiple-range test. All statistical analyses were performed using SAS statistical programs .
RESULTS AND DISCUSSION
The effects of different fat sources added in broiler diets on broiler meat composition are shown in Table 2. The moisture content of thigh meat was significantly higher in broilers led a diet containing SO (P
The crude fat content of thighs and breasts were found to be statistically different (P
Cholesterol, triglyceride, HDL, and LDL values in serum of broilers fed with diets containing different fat sources are shown in Table 3. Cholesterol, HDL, and LDL values in blood serum of broilers fed with different fat sources were significantly different (P
All studies, however, do not agree. Fan et al. , for example, found that diets containing different fat sources did not affect blood cholesterol values. Although the HDL value was the highest in the groups fed with diet containing CO, this value was lowest in the groups fed with tallow added in diet. Although the LDL value was highest in groups fed with diet containing T, this value was lowest in groups fed with diet containing SFO. In the current study, HDL values were highest in the groups fed the diet containing CO and lowest in the groups fed T. Contrary to this, LDL values were highest in groups fed T and lowest in groups fed the diet containing SFO. When previous research of HDL and LDL was examined, it was concluded that the blood and products of animals had high HDL and low LDL values. On the other hand, several researchers [10, 31, 32, 33] have shown that low HDL and high LDL are values associated with atheroschiorosis. Researchers [31, 32] have also shown that increased serum HDL is able to decrease the negative effect of high blood cholesterol.
The effect of sex on HDL and LDL values was found to be statistically significant. Although HDL values were high in males (P
CONCLUSIONS AND APPLICATIONS
1. The effect of fat sources in the feed on the moisture, ash, and fat content of thigh and breast of broilers was different. The different fat sources did not have any statistical significant effect on protein content of thigh or breast meat.
2. The highest values of cholesterol, triglyceride, HDL, and LDL were in the groups fed with the diets containing CO, SFO, CO, and T, respectively.
3. The lowest values of cholesterol, triglyceride, HDL, and LDL were in the groups fed with diets containing SFO, CO, T, and SFO, respectively.
4. The amount of HDL in male chickens and the amount of LDL in female chickens were determined to be significantly higher than in the opposite sex.
5. Because of human health concerns, for example, atheroschlorosis disease, it was shown that the relative high HDL and low LDL values were positive attributes of broiler meat in the human diet.
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This study was supported in part by Adnan Menderes University, Revolving Fund Accountancy, 09100, Aydin, Turkey.
M. Ozdogan1 and M. Aksit
Adnan Menderes University, Faculty of Agriculture, Department of Animal Science, 09100 Aydin, Turkey
1 To whom correspondence should be addressed: email@example.com; firstname.lastname@example.org.
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