©2008 Poultry Science Association, Inc.
Effect of Dietary Fat Type on Broiler Breeder Performance and Hatching Egg Characteristics M. Bozkurt,* M. C ¸ abuk,†1 and A. Alc¸ic¸ek‡ *Poultry Research Institute, Erbeyli, Aydın-Turkey; †Department of Poultry Science, Akhisar Vocational School of Celal Bayar University, Manisa-Turkey; and ‡Department of Animal Science, Agricultural Faculty of Ege University, Bornova, Izmir-Turkey
Primary Audience: Hatching Egg Producers, Researchers, Nutritionists, Extension Personnel SUMMARY The effect of dietary fat type on broiler breeder performance was evaluated in the experiment. Three different fat sources (sunflower oil, fish oil, tallow) were supplemented into a corn-soybean meal-based broiler breeder diet. The control diet included no supplemental fat. All diets were isocaloric and isonitrogenous. Feeding of experimental diets was initiated when breeders (Ross 508) were 22 wk old. Body weights of hens and males were not affected by dietary treatments during the experimental period. Tallow supplementation to breeder diet significantly decreased hen-day egg production and cumulative settable egg yield (P < 0.01) when compared with other treatments. Hens fed with tallow and sunflower oil-added diets produced significantly heavier settable eggs than control and fish oil treatments. However, settable egg weight of hens fed with fish oil was lower than other dietary treatments (P < 0.01). Egg yolk weight, albumen weight, and eggshell weight were not affected by dietary treatments. These data suggest that supplementation of different fat sources at a level of 1.5% to the corn-soybean meal diet may affect egg production performance, fertility, egg weight, chick weight, hatch of eggs set, and specific gravity without any adverse effects on body weight and settable egg characteristics. Key words: broiler breeder, dietary fat, performance, settable egg characteristics 2008 J. Appl. Poult. Res. 17:47–53 doi:10.3382/japr.2007-00008
DESCRIPTION OF PROBLEM Broiler breeder diets influence subsequent egg production performance [1, 2] and also embryogenesis and hatchability of broiler eggs [3– 5]. The addition of 5% poultry fat to broiler breed diets, without increasing ME intake, has been reported to increase egg weight and egg production [6]. Furthermore, Brake [2], who re1
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ported that addition of 2, 4, or 6% poultry fat to broiler breeder diets, with respective increases in ME intake, increased egg production, and feed conversion ratio. The number of chicks produced per hen was maximized with 4% poultry fat included in the diet. There are data in the literature that also report the effects of changes in dietary fatty acid (FA) on proportional changes in yolk FA [7, 8], and this has the potential
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48 of influencing embryonic FA metabolism and overall embryonic growth [4]. Although its effects on laying hens have been well documented since the 1960s [9–12], the actual importance of dietary linoleic acid in broiler breeder nutrition has not been clearly established. A number of reports have also detected no effect of up to 5% supplemental fat on egg weight of breeders [1, 2] fed on cornwheat-based diets. Tallow, lard, and fish oil processing by-products have become more available to the poultry industry in some states as a cheaper dietary fat source. There is also a lack of information on the effects of dietary tallow, fish oil, and sunflower oil through the laying period on the performance of broiler breeders. In this study, inclusion of the 3 different fat sources that differ in fatty acid profile (sunflower oil, fish oil, tallow) in standard breeder diets at the level of 1.5% on egg production and reproductive performance was examined.
MATERIALS AND METHODS Male and female Ross-508 broiler breeder chicks [13] were placed in an open house with natural ventilation and reared in conventional litter floor pens with standard management practices. Birds were exposed to natural day length through the growing period (1 to 21 wk). Amount of feed was adjusted weekly during the growing period to maintain BW gain as recommended by Ross Breeders [13]. The experimental study was initiated when the birds were 22 wk of age. Briefly, 50 hens and 5 males were randomly assigned to each of 16 breeder pens (4 treatments with 4 replicates per treatment) in a curtain-sided breeder house. Each pen was equipped with 1 automatic waterer, 6 hanging feeders, and one 12-hole nest box. The floor of breeder pens was covered with pine shaving as litter material. With the exception of hand feeding, the housing was comparable with commercial standards. Hens were exposed to natural environmental conditions at the subtropics climatic zone from February to September through the laying period. Upon movement to the breeder house at 22 wk of age, daylength was increased by 1-h increments per wk to 16 h at start of lay (26 wk) using a combination of natural and incandescent light. Diets were adjusted weekly to maintain
recommended body weights during the prelay period (22 to 25 wk). Weekly incremental increases in feed began before lay so that feed rations were adjusted from 125 g/bird per d at housing to 165 g/bird per d at initiation of lay. After egg lay commenced (26 wk) daily feed allotment was sustained continuously at 165 g/ hen per d, and energy intake was 462 kcal/hen day through the 22 to 58 wk experimental period. Males fed together with hens in the same feeders; separate-sex feeding was not applied. So, the amount of daily feed allowance for males was assumed to be similar to females. Dietary treatments initiated at wk 22 and all diets were formulated to meet or exceed National Research Council [14] specifications. The experimental diets contained various types of added fat. An antioxidant combination was added into 3 experimental fat sources (0.5 g/kg of fat) at the beginning of the study. Fat sources were stored in plastic barrels of 200 kg during the experimental period. The antioxidant combination provided the following quantities per gram of fat: butylated hydroxyanisole, 7.5 mg; ethoxyquine, 40 mg; butylated hydroxytoluene, 90 mg; and citric acid, 30 mg. Fatty acid profiles of the experimental fats were determined according to the method of the Association of Analytical Chemists [15] and are shown in Table 1. The fatty acid methyl esters were prepared from lipid samples and from subsequent fatty acid profiles obtained by gas-liquid chromatography. The fatty acid methyl esters were analyzed using a 50 × 0.25 mm inside diameter WCOT fused-silica CP-Sil 88 capillary column installed on a flame ionization detector [16]. All diets were isocaloric and isonitrogenous (Table 2). Diet 1 was a common corn-soybean mash diet and contained no added fat (CT); diets 2, 3, and 4 contained sunflower oil (SO), fish oil (FO), and beef tallow (TW), respectively. All of the birds were weighed individually at wk 22, 34, 46, and 58. Egg production and percent settable eggs per hen were recorded daily. Egg production was calculated as hen-day egg production (%) of total laid eggs per each replicate. Percent settable eggs per hen was defined as ratio of total settable eggs to total laid eggs per each treatment. Mortality was recorded daily and feed allowance adjusted accordingly. Eggs were collected 4 times a day and recorded as nest- or
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Table 1. Fatty acid composition of the fats used in the present study (% of total fatty acid) Fatty acid
Sunflower oil
Fish oil (anchovy)
Tallow
— — 6.41 0.16 3.18 22.73 66.35 0.11 — — — — — 9.59 89.35 66.35 0.11 603.18
3.04 7.72 18.62 9.44 7.83 23.09 4.86 2.65 1.26 1.68 4.32 0.86 11.77 37.21 59.93 6.54 20.86 0.31
0.98 12.67 25.33 3.92 8.36 25.72 15.56 4.53 — 1.05 0.23 — — 47.34 51.01 16.61 4.76 3.49
C12:0 lauric C14:0 myristic C16:0 palmitic C16:1 palmitoleic C18:0 stearic C18:1n-9 oleic C18:2n-6 linoleic C18:3n-3 linolenic C18:4n-3 stearidonic C20:4n-6 arachidonic C20:5n-3 eicosapentaenoic C22:5n-3 docosapentaenoic C22:6n-3 docosahexaenoic Σ saturated Σ unsaturated Σ n-6 Σ n-3 Σ n-6/n-3
Table 2. Ingredient and chemical composition of experimental diets Ingredient (%) Yellow corn Wheat Soybean meal (48% CP) Sunflower meal (31% CP) Sunflower oil Fish oil (anchovy) Tallow (beef) Limestone Dicalcium phosphate Salt Vitamin premix1 Mineral premix2 DL-Met Composition, analyzed (%) DM CP (N × 6.25) EE CF Crude ash Starch Sugar Total calcium Total phosphorus ME (kcal/kg) Lys (calculated) Met + Cys (calculated) 1
Control
Sunflower oil
Fish oil
57.28 10.00 19.84 3.34 — — — 7.60 1.24 0.25 0.25 0.10 0.10
52.90 10.00 16.46 9.81 1.50 — — 7.34 1.27 0.25 0.25 0.10 0.12
53.23 10.16 16.50 9.32 — 1.50 — 7.31 1.26 0.25 0.25 0.10 0.12
53.46 10.38 16.21 9.17 — — 1.50 7.30 1.26 0.25 0.25 0.10 0.12
88.96 16.10 3.03 2.93 9.64 40.46 5.22 3.24 0.72 2,823 0.81 0.68
89.64 15.98 4.69 4.69 9.23 37.30 4.93 3.18 0.69 2,813 0.80 0.67
89.12 16.04 4.58 4.23 9.81 37.16 4.63 3.32 0.68 2,792 0.80 0.67
90.27 15.87 4.43 4.98 9.86 38.09 4.07 3.36 0.73 2,789 0.80 0.67
Tallow
Vitamin premix (per kg of diet): vitamin A, 16,000 IU; vitamin D3, 3,000 IU; vitamin E, 40 IU; vitamin K3, 2.5 mg; vitamin B1, 2.5 mg; vitamin B2, 10 mg; nicotinamide, 50 mg; calcium D-pantothenate, 15 mg; vitamin B6, 6.25 mg; vitamin B12, 0.035 mg; folic acid, 15 mg; D-biotin, 0.045 mg; choline chloride, 150 mg. 2 Mineral premix (mg/kg of diet): Mn, 80; Fe, 80; Zn, 60; Cu, 8; Co, 0.2; I, 0.5; Se, 0.15.
50 floor-laid, cracked, broken, or soft-shelled eggs. Only nest eggs that were not dirty, misshapen, broken, cracked, excessively small, or doubleyolked were classified as settable eggs and stored in a cooler until set. Random samples of 128 eggs (32 settable eggs per replicate pen) for 2 consecutive days every week from each treatment were weighed individually to determine average egg weight. Additionally, 60 newly hatched chicks (21.5 d incubation) per treatment (15 chicks per replicate pen) were weighed individually at the hatchery on a weekly basis. One hundred twelve settable eggs per replicate pen were set for incubation weekly between 28 and 58 wk of age. Eggs were incubated in Petersime model S20 incubator. Incubator was set at 37.6°C dry bulb and 28.6°C wet bulb temperatures. Eggs were candled on d 10 of incubation for determination of infertile eggs. All infertile eggs were opened and examined macroscopically for evidence of embryonic mortality. Fertility was expressed as rate of fertile eggs to total eggs set. On d 19, eggs were transferred to the hatching cabinet of the same incubator for hatching. Hatching incubator was set at 37.5°C dry bulb and 29.2°C wet bulb temperatures. Number of eggs that hatched was recorded at 21.5 d of incubation. Hatchability of fertile eggs was expressed as rate of hatching chicks to fertile eggs, and percentage cumulative hatchability was expressed as percentage of hatching chicks to the total eggs set. Settable egg quality was measured at 28, 34, 40, 46, 52, and 58 wk of breeder hen age. Settable egg quality parameters included egg specific gravity (ESG), egg yolk weight (EYW), and albumen weight (EAW). The EYW and EAW were expressed as percentages of total egg weight. Randomly collected settable eggs (6 per pen) were used for evaluation of settable egg quality parameters. Therefore, 96 settable eggs were examined for each test period (total of 576 settable eggs). The method for measurement of ESG was as described by Hamilton [17]. The standard techniques for the proximate analysis were used to determine the nutrient concentrations in the diets [18]. The experimental diets were also analyzed for starch, sugar, total calcium, and phosphorus, according to the Association of German Agricultural Analysis and Research Institutes (VDLUFA) method [18]. Me-
JAPR: Research Report tabolizable energy content of the diets was calculated based on chemical composition [19]. The data were analyzed using the GLM procedure of SAS [20]. Significant differences between treatment means were separated using Duncan’s multiple range test with a 5% probability (P < 0.05).
RESULTS AND DISCUSSION Body weights of hens and males determined at 22, 34, 46, and 58 wk of age are shown in Table 3. Hen and male body weight was not affected by dietary fat addition through the entire experimental period. It was demonstrated in an early report [6] that added animal or vegetable fat at the 5% level did produce slightly but consistently higher female body weights after peak egg production. Body weight of hens fed SO and TW added diets were slightly but consistently higher than CT hens, but differences among treatments were not significant (P > 0.05). The results of the current study are similar to those in an earlier study of broiler breeder hens [1] fed corn oil, poultry oil, and lard supplemented diets at the level 1.5 to 3%. The dietary treatments had no significant effect on male body weight determined at 22, 34, 46, and 58 wk of age (P > 0.05; Table 3). Production and reproductive performance characteristics of breeder hens are shown in Table 4. The inclusions of fats to the diet have no adverse effects on egg production of broiler breeders in the current study except the TW treatment. Tallow supplementation significantly depressed egg production below all other treatments. However, in previous reports inclusion of dietary fats such as tallow or lard rich in saturated fatty acids had no deleterious effect on egg production of broiler breeders and layers, respectively [5, 21], whereas in other cases an increase in egg production was reported [2, 6]. On the other hand, this finding is consistent with report of Peebles et al. [5] who proposed that increased saturation level of dietary fat may have adverse effects on egg production. The more saturated fatty acid content of TW diet might be responsible for slower follicle formation when compared with SO and FO added diets that contained less saturated fatty acid. A significantly increased egg production rate was reported by some workers [2, 6] when an animal-vegetable
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Table 3. The effect of dietary fat type on body weights of broiler breeder hens and males Age (wk)
Control
Sunflower oil
Fish oil
Tallow
SEM
Probability
Female
22 34 46 58
2,128.80 3,549.47 3,547.39 3,733.22
2,139.16 3,606.40 3,600.05 3,804.16
2,137.18 3,509.84 3,535.62 3,784.27
2,126.92 3,561.09 3,614.42 3,756.56
18.36 23.86 26.90 31.05
0.9550 0.0805 0.1028 0.3906
Male
22 34 46 58
3,214.41 4,278.23 5,068.68 5,533.09
3,187.72 4,251.14 5,144.39 5,512.73
3,223.86 4,318.67 5,095.78 5,564.22
3,236.20 4,257.08 5,167.55 5,591.17
22.51 37.29 44.63 61.27
0.6238 0.5090 0.3695 0.4640
Sex
fat mixture was added to the breeder diet. Settable egg rate of hens fed SO was reduced significantly when compared with CT and FO treatments. Hens fed the SO and TW added diets produced heavier eggs (62.30 and 62.12 g, respectively) than hens fed the control diet (61.56 g), whereas egg weight of hens fed the FO-supplemented diet was the smallest (61.03). The inclusions of fats to diets of commercial layers [10– 12, 22, 23] and broiler breeders [6] have been shown to increase egg weight. However, in some recent studies [1, 5] it was demonstrated that poultry fat and lard supplementation to broiler breeder diets up to the 3% level did not significantly affect egg weight. Similarly, other workers found no effect of feeding menhaden fish oil supplemented diets on egg weight and egg mass [24, 25]. Contrary to those reports, fish oil supplementation to broiler diet decreased settable egg weight significantly (P < 0.01) compared with SO, TW, and CT treatments in this study. Consistent with the results of this experiment,
Van Elswyk et al. [26] demonstrated that egg weight of laying hens fed menhaden fish oil was decreased as compared with that of hens fed animal-vegetable oil following a 6-mo feeding (P < 0.05). Van Elswyk et al. [27] suggested that increasing dietary n-3 fatty acid content might cause a decrease in circulating triglycerides of birds, thus limiting availability of lipids for yolk formation. This hypothesis could partially explain the lower egg weight and associated chick weight found in birds fed FO in this study. Dietary added fats had no significant effect on the rate of double-yolked eggs and hen liveability in this experiment (P > 0.05; Table 4). Consistent with results of previous broiler breeder experiments [1], the moderate energy (2,800 kcal/kg) and fat addition level (1.5%) applied in this study had no detrimental effect on hatchability of fertile eggs. Brake et al. [6] demonstrated that hens that consumed 5% added poultry fat diets had significantly lower fertility (90.6 vs. 93.5%) and hatchability (90.6 vs. 91.8%) than those hens fed a no-fat-added, cornsoybean-based control diet.
Table 4. Effect of dietary fat type on egg production and reproductive performance of broiler breeders Item Egg production (%), hen-day Egg weight (g), n = 8,192 eggs Settable egg (%) Total settable eggs (per hen) Double yolked egg (%) Liveability (%) Fertility (%) Hatchability of fertile eggs (%) Hatchability of total eggs set (%) Chick weight (g)
Control a
64.65 61.56b 85.23a 123.29a 0.94 94.78 91.43a 91.44 83.62a 39.29b
Sunflower oil a
64.67 62.30a 83.76b 121.52ab 0.97 92.18 86.89b 90.25 78.49b 40.13a
Means with different superscripts in row differ at P < 0.05.
a–c
Fish oil a
63.36 61.03c 84.90a 120.65ab 1.09 95.30 89.97a 91.19 81.96a 39.25b
Tallow
SEM
Probability
b
0.51 0.11 0.35 1.83 0.23 2.61 0.77 0.55 0.96 0.15
0.0001 0.0001 0.0183 0.1656 0.9108 0.5620 0.0005 0.4697 0.0023 0.0001
61.84 62.12a 84.39ab 117.08b 1.14 90.62 90.36a 91.09 82.35a 40.05a
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Table 5. The effect of dietary fat type on the settable egg characteristics of broiler breeders Settable egg characteristic
Control
Sunflower oil
Fish oil
Tallow
SEM
Probability
Egg albumen weight (g) Egg yolk weight (g) Eggshell weight (g) Egg specific gravity (g/cm3)
38.51 19.19 7.90 1.0791c
38.50 19.23 7.84 1.0884a
38.13 19.14 7.96 1.0823bc
38.55 19.26 7.96 1.0851b
0.25 0.13 0.06 0.001
0.6444 0.9191 0.5366 0.0001
Means with different superscripts in row differ at P < 0.01.
a–c
It was demonstrated by Peebles et al. [1] that increased saturation of dietary fat increased ESG and eggshell weight per unit of surface area. In the present study, ESG of eggs from hens fed SO and TW supplemented diets, which have increased saturation level, were significantly higher than those hens fed the CT diet (Table 5). Furthermore, it was proposed that increased saturation level of fat may have an adverse effect on egg production and eggshell quality [1]. Previous reports pointed out that increased dietary fat content had no significant effect on ESG of laying hens [28] and broiler breeders [1]. Although adding poultry fat to a broiler breeder diet decreased eggshell percentage weight in an earlier work [2], dietary fat addition had no significant effect on ESW, EYW, or EAW in the current study. These data confirm earlier work [5] that reported dietary poultry fat and corn oil addition in broiler breeder diet had no significant effect on EYW, EAW, and ESW. Another earlier work [10] reported a linear increase in yolk weight with increased increments of dietary fat. Because the eggshell cuticle is partially composed of lipid, the fat content of the hen diet may also modify the cuticle’s impact on egg water loss and embryogenesis [4]. Moreover, fatty acid oxidation is the primary source of energy and metabolic water for developing embryos [29]. Furthermore, embryos appear to preferentially absorb certain fatty acids rich in long-chain polyunsaturated fatty acids [26]. However, 3 different dietary fat supplementations differing in fatty acid profile had no significant effect on egg weight and hatchability of fertile eggs in this experiment. It was shown by Vilchez et al. [30] that supplementation of diets for Japanese quail hens with palmitic acid or oleic acids decreased embryonic mortality when compared with linoleic
or linolenic acid supplements. On the other hand, Halle [31] did not find detrimental effects on reproductive performance of broiler breeder hens due to dietary fat supplements of up to 50 g/kg of palm oil or safflower oil. Although the beneficial effect on egg weight of SO supplementation to breeder diets that are rich in linoleic acid was observed, the detrimental effect on fertility was unexplained in the current study. Blesbois et al. [32] proposed that the lipid composition of the diet might modify the fatty acid composition of the semen and its fertilizing ability. In addition, broiler breeders fed on FO (salmon) diet gave significantly higher fertility rates (96%) than that of hens fed a corn oil diet (91.6%). Although the fatty acid composition of spermatozoa showed notable amounts of 20:4n6 and 22:4n-6, elongated PUFA, and these essential fatty acids were synthesized from dietary 18:2n-6 (linoleic acid), it could not explain the lower fertility results of SO treatment. It is noticeable that there are limited data about fat and FA component of breeder diets on fertility metabolism, although detailed reports were available on embryonic growth and hatchability.
CONCLUSIONS AND APPLICATIONS 1. In comparison with the control, supplementation of the corn-soybean-based breeder diet had the following effects: SO increased egg weight, chick weight, and ESG, but decreased percentage of settable eggs per hen, fertility, and hatchability of the eggs set; FO decreased egg weight; and TW increased egg weight, chick weight, and ESG, but decreased egg production and settable eggs per hen. 2. Maternal diet can affect embryo growth and subsequent hatching chick weight without having an effect on hatchability.
BOZKURT ET AL.: EFFECT OF DIETARY FAT TYPE 3. From an economical point of view, different dietary fat strategies had no beneficial effects on broiler breeder productivity in terms of total settable egg and total hatching broiler chick yield. However, further research is needed to elicit the dietary supplemented sunflower oil and tallow on settable egg weight and hatching broiler chick weight with respect to chick quality including progeny performance tests.
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