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Effects of different limestone particle sizes in the diet of broiler breeders post molting on their performance, egg quality, incubation results, and pre-starter performance of their progeny
Effects of different limestone particle sizes in the diet of broiler breeders post molting on their performance, egg quality, incubation results, and pre-starter performance of their progeny I. J. M. Bueno,∗ D. Surek,∗ C. Rocha,∗ V. G. Schramm,∗ K. Muramatsu,∗ F. Dahlke,†,1 and A. Maiorka∗ ∗
Department of Animal Science, Federal University of Paran´ a, Curitiba, PR, Brazil; and † Laborat´ orio de Avicultura, Department of Animal Science, Federal University of Santa Catarina, Florian´ opolis, SC, Brazil
Key words: broiler breeder, calcium, egg quality, incubation 2016 Poultry Science 0:1–7 http://dx.doi.org/10.3382/ps/pev438
INTRODUCTION
(Al-Batshan, et al. 1994; Rayan et al., 2010). Eggshell porosity and thickness strongly influence embryo development and hatchling quality (Narushin and Romanov, 2002). The production of good-quality hatchlings requires eggs to present more than 1.080 egg specific gravity (Roque and Soares, 1994; Narushin and Romanov, 2002). Induced molting is a commercial practice that aims at improving the reproductive performance of broiler breeders and at restoring egg quality (Verheyen and Decuypere, 1986; Buhr and Cunninghan, 1994; Tona et al., 2002). Many studies have reported that eggshell and albumen quality, hatchability, and juvenile growth performance are positively influenced by molting (Decuypere and Verheyen, 1986; Attia et al., 1994; Tona et al., 2002). Relative hatchling weight (hatchling weight to egg weight ratio) is higher after than before molting in mature broiler breeders (Tona et al., 2002), and the eggs of molted hens lose less weight during incubation, possibly due to better eggshell structural characteristics (Christensen and McCorkle, 1982). Calcium solubility in layers is influenced by several factors, including calcium source, particle size, time of retention in the gizzard, and interaction with other feedstuffs (Ajakaiye et al., 1997). Studies with layers
Many factors affect the chick embryo and consequently hatchling quality and broiler growth potential, including egg storage, duration of incubation, and breeder age (Almeida et al., 2008; Hamidu et al., 2011). Previous studies have determined that egg weight (Ulmer-Franco et al., 2010) and hatchling weight (Vieira et al., 2005) increase as broiler breeders age. In addition, albumen characteristics, albumen/yolk ratio, embryo survival, and hatchability are also influenced by broiler breeder age (Vieira and Moran, 1998, 1999). According to Zakaria et al. (2009) weight loss is higher in eggs of older breeders’ as compared with those of younger breeders, and may be ascribed to the deterioration of eggshell quality. This is a result of the accumulation of fat in the uterus, which impairs calcium deposition in the eggshell, intestinal calcium absorption, and calcium release from the bloodstream, resulting in increasingly thinner eggshells as breeder’s age C 2016 Poultry Science Association Inc. Received May 29, 2015. Accepted November 13, 2015. 1 Corresponding author: [email protected]
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teristics, and breeder performance, egg characteristics, eggshell quality, incubation performance, chick quality and yield, chick pre-starter live performance, and chick bone characteristics were determined. There was no significant difference (P > 0.05) in the rate of lay, percentage of non-settable eggs, egg weight, egg shape index, egg specific gravity, eggshell weight, thickness, and percentage hatchability and egg weight loss of broiler breeders fed with diets with different limestone particle sizes. The chick quality and yield, chick pre-starter live performance, and chick bone characteristics were not affected (P > 0.05) by any of the limestone particle sizes. It was concluded that live and reproductive performance parameters of broiler breeders post molting is not affected by limestone particle size in the feed.
ABSTRACT An experiment was conducted to test the hypothesis that a coarse limestone diet improves productivity, reproductive performance and the calcium utilization of molted broiler breeders. In total, 640 broiler breeder females, 73-week-old and sixty-four 27-week-old cockerels, Cobb 500, were evaluated during 10 weeks, according to a randomized block design composed of 4 treatments with 8 replicates each. Treatments consisted of diets with the inclusion of 100% fine limestone - fine PS (0.2 mm GMD - geometric mean diameter); PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD; PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD; and PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. Calcium retention in the gizzard of the breeders, bone charac-
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BUENO ET AL.
have reported long gizzard retention times of large particles of limestone, which release calcium slowly and uniformly during the period of eggshell formation (Zhang and Coon, 1997; Leeson and Summers, 1997), thereby allowing the retention of calcium in the medullary bones of the birds (Rao and Roland, 1992). Manangi and Coon (2006) observed the dietary inclusion of limestone with larger particles reduced phosphorus excretion and improved egg specific gravity, which is an eggshell quality measurement. The objective of the present study was to compare the dietary inclusion of limestone with different particle sizes on the live performance of broiler breeders, eggshell quality, parental and progeny skeletal structure, and broiler performance.
The experiment was approved by the Ethics Commission for Experimental Use of Animals of the Federal University of Paran´ a, Brazil (0431/2011). A commercial flock of Cobb 500 broiler breeders (640 females and 64 males) was utilized. Before the experimental period, all birds were submitted to the same management practices, following the Cobb 500 Breeder Management Guide (Cobb-Vantress, 2005). At 22 weeks of age the flock was transferred to a production house (open-side house), where they remained up to 63 weeks of age. The females were submitted to the traditional system of induced molting at 65 weeks of age, and then transferred to the experimental house at 73 weeks of age and distributed in 32 pens, measuring 12.0 m2 each (3.0 × 4.0 m). The experimental house was open-sided with fibrocement roof and polypropylene side curtains, and had a concrete floor covered with new wood-shaving litter. The house was equipped with trough feeders for females, tube feeders for males, nipple drinkers, and nests for manual egg collection. Artificial light was supplied by incandescent lamps. Birds were individually weighed and distributed to the pens according to 2 weight classes: light (2.5 to 3.0 kg) or heavy (3.1 to 3.5 kg) in order to obtain homogenous experimental units. Sixty-four 27-week-old cockerels (3.700 ± 0.050 kg) were housed with the females. During the experimental period, eggs were collected five times daily (08:00, 10:30, 13:00, 15:30, and 17:30 h) and classified as settable or non-settable (cracked/broken) eggs.
Experimental Design and Diets The chicks were randomly allocated into 4 dietary treatments, and each treatment had 8 replicates with 20 hens and 2 cockerels per experimental unit. Birds were distributed in a randomized complete block design where weight class was the criterion for the establishment of the blocks. The experimental treatments consisted of diets containing limestone with different
Ingredients (%)
FPS1
PS12
PS23
PS34
Corn Soybean meal 46% CP Limestone Kaolin Dicalcium phosphate Soybean oil Vitamin and mineral5 supplement1 Sodium chloride Sodium bicarbonate DL-methionine Choline chloride L-lysine
66.4 22.4 6.60 1.70 1.20 0.50 0.40 0.29 0.20 0.14 0.09 0.03
66.4 22.4 6.60 1.70 1.20 0.50 0.40 0.29 0.20 0.14 0.09 0.03
66.4 22.4 6.60 1.70 1.20 0.50 0.40 0.29 0.20 0.14 0.09 0.03
66.4 22.4 6.60 1.70 1.20 0.50 0.40 0.29 0.20 0.14 0.09 0.03
Determined chemical composition Moisture (%) 11.49 Crude protein (%) 15.12 Calcium (%) 3.08 Ash (%) 13.69 Total phosphorus (%) 0.50
11.59 15.11 3.02 13.07 0.49
11.60 15.04 3.10 13.43 0.49
11.64 15.11 3.13 13.28 0.50
(on as-fed basis) 2,85 2,85 2,85 0.42 0.42 0.42 0.18 0.18 0.18 0.71 0.71 0.71 0.35 0.35 0.35 0.16 0.16 0.16
2,85 0.42 0.18 0.71 0.35 0.16
Calculated chemical composition Metabolizable energy (kcal/kg) Available phosphorus (%) Sodium (%) Digestible lysine (%) Digestible methionine (%) Digestible tryptophan (%)
1 FPS: 100% fine limestone (0.2 mm GMD - geometric mean diameter). 2 PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD. 3 PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD. 4 PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. 5 Levels supplied/kg of diet: vitamin A 12,200 UI; vitamin D3 3,700 UI; vitamin E 21.6 UI; vitamin K3 2.9 UI; vitamin B1 3.2 mg; vitamin B2 12.6 mg; vitamin B6 5.5 mg; vitamin B12 0.046 mg; pantothenic acid 20 mg; niacin 40 mg; folic acid 4 mg; biotin 0.29 mg; selenium 0.20 mg; copper 20 mg; iron 50 mg; manganese 115 mg; zinc 100 mg; iodine 2 mg.
Table 2. Limestone geometric mean diameter (GMD), geometric standard deviation (GSD), and calcium content. Parameters Limestone Limestone Limestone Limestone
0.2 1.0 2.0 3.0
GMD GMD GMD GMD
GMD mm
GSD %
Ca %
0.23 1.13 1.91 2.92
1.11 1.42 1.19 1.32
38.2 38.2 38.2 38.2
particle sizes, as determined by geometric mean diameter (GMD): fine particle size (FPS), with 100% fineparticle limestone (GMD of 0.2 mm); 1.0 mm particle size (PS1) with 30% fine limestone and 70% limestone with 1.0 mm GMD; 2.0 mm particle size (PS2), with 30% fine limestone and 70% limestone with 2.0 mm GMD; and 3.0 mm particle size (PS3), with 30% fine limestone and 70% limestone with 3.0 mm GMD. Feeds was in mash form and formulated on a corn and soybean meal basis (Table 1). All diets contained equal calcium and limestone levels. Limestone was analyzed for GMD, particle-size distribution (geometric standard deviation – GSD), and calcium content (Table 2). Females in all treatments were offered the same amount of feed calculated according to egg production (5% production – 130 g ration; 10% - 133 g; 20% - 136 g; 30%
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MATERIAL AND METHODS
Table 1. Composition and nutritional levels of the experimental diets.
LIMESTONE IN POST MOLTING BROILER BREEDER DIETS
- 140 g; 40% - 146 g; 50% - 152 g; 60% - 158 g; > 70% - 164 g), which was measured weekly. Males were fed according to their body condition score, which was evaluated weekly. Feed was supplied in the morning. Water was offered ad libitum.
Measured Parameters
Hatching rate was calculated as the ratio between viable hatchlings and the total number of incubated eggs. Hatch yield was calculated as the ratio between egg weight at setting and hatchling weight. In order to evaluate fertility and embryo mortality, non-hatched eggs were counted and submitted to embryo diagnosis. In total, 1,456 good quality chicks (364 per treatment) were reared in different pens in an experimental broiler house at a density of 12 chicks/m2 at 30 to 32◦ C until 7 days old, and live performance (feed intake, weight gain, and feed conversion ratio) was evaluated. Chicks were housed according to their breeder’s treatment, totaling 14 replicates with 26 birds each. A photoperiod of 22 h of light and 1 h of dark was applied. Birds were fed a standard broiler pre-starter diet (3,000 kcal metabolizable energy/kg, 23.00% crude protein) ad libitum. At the end of the experimental phase, 3 chicks per replicate were sacrificed by neck dislocation and the right tibiae were collected for the determination of calcium and ash contents. When hens were 83 weeks old, 8 hens per treatment were sacrificed after 8, 10, 12, and 28 hours of feed fasting. The digestive tract was collected, and gizzard content was removed, weighed, and dried in a forcedventilation oven (16 h at 105◦ C). Gizzard content was analyzed for dry matter, calcium, and ash contents (AOAC, 1995) in order to estimate calcium (limestone) retention percentage in the gizzard at different times after feeding. Both tibiae were collected: the left tibiae was used to measure bone density and breaking strength, whereas the right tibiae was analyzed for ash and calcium contents. The left tibia was cooked in boiling water for one minute to remove meat, proximal cartilage, and the fibula, and then immersed in ethylic ether for 24 h for the complete removal of fat residues. After complete ether evaporation, bones were dried in an oven at 65 ◦ C for 24 h, weighed, and placed in a muffle at 600◦ C for subsequent determination of bone ash and calcium contents (AOAC, 1995). The right tibiae were subjected to the same procedure of meat, cartilage, and fat removal. After drying, tibiae were weighed (Tecnal, model BG – 400, Piracicaba, Brazil), and their length was measured using a digital caliper. To determine bone density, Archimedes’ principle was applied (Rath et al., 1999). After that, bones were dried again in an oven (65◦ C for 24 h) and their breaking strength was determined by applying a perpendicular force at the speed of 5 mm/min with a 30 mm diameter cylindrical knife at the midpoint between epiphyses (EMIC apparatus, model DL2000, INSTRON, Paran´ a, Brazil). Bone breaking strength was determined as the maximum strength required to break the bone completely.
Statistical Analysis The assumptions of residue normality and homoscedasticity were analyzed by the tests of
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Rate of lay was evaluated between weeks 74 and 83. This was calculated as the ratio between total egg production and number of hens, and expressed as a percentage. The percentage of non-settable (cracked or broken) eggs relative to total egg production was also evaluated. Egg characteristics (weight and egg shape index) and eggshell quality (egg specific gravity, eggshell absolute weight, eggshell weight relative to total egg weight, and eggshell thickness) were determined twice weekly between weeks 74 and 77 in all eggs produced on the day of evaluation. Egg specific gravity was determined using the flotation method (Freitas et al. 2004). Egg shape index was determined by measuring intact egg width and length with a digital caliper (Lee Tools, model 684132, S˜ ao Paulo, Brazil) for the calculation of width to length ratio. For the determination of eggshell parameters, eggs were individually identified and broken. Eggshells were washed under running water and dried in an oven at 35o C for 15 hours. Eggshells were then weighed and their relative weight calculated. Eggshell thickness was measured at 3 different regions with the digital caliper to calculate average eggshell thickness. Both eggs and eggshells were weighed in a digital precision scale (0.001 g). Incubation responses were evaluated using the eggs laid between weeks 78 and 79. The eggs were collected, disinfected, and individually weighed and identified. Until setting, eggs were stored for a maximum period of 7 days in an environmentally controlled room (19 to 21◦ C and 60 to 80% RH). Six trays of 96 eggs were incubated per treatment (one tray per replicate). Eggs were incubated in a CASP machine (model Mg124, CASP, Amparo, SP, Brazil) at 37.5o C (99.5 Fo ) and 52.5% RH in trays identified per replicate and randomly distributed in the incubation trolleys. On d 18, eggs were transferred to a CASP Hatcher (model Ug21, CASP, Amparo, SP, Brazil) at 36.5◦ C and 65% RH until hatch. Egg trays were weighed empty and with the eggs before being placed in the incubator and at the time of transfer to the hatcher in order to determine egg weight loss during incubation. Hatchlings were removed from the hatcher, counted, and weighed at the 504th incubation hour. Each hatchling was visually examined and classified as a first- or second-quality chick. First-quality chicks were defined as clean, dry, free from contamination, free of deformities (no skin lesions, well-formed beak, good leg conformation), and with the navel completely closed, with no yolk sac or dried membranes protruding from the navel.
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BUENO ET AL. Table 3. Post-molting rate of lay and egg characteristics of broiler breeders fed diets containing limestone with different particles sizes. P6 Parameters
FPS1
PS12
PS23
PS34
SEM5
Linear
Quadratic
Rate of lay (%) Cracked/broken eggs (%) Egg weight (g) Egg shape index Egg specific gravity (g/ml) Eggshell weight (g) Eggshell thickness (mm) Eggshell (%)
69.8 5.26 71.0 0.73 1.07 6.36 0.39 8.95
72.4 5.80 71.0 0.73 1.06 6.39 0.39 8.99
69.9 5.38 71.2 0.73 1.06 6.31 0.39 8.88
69.5 5.26 70.5 0.73 1.06 6.33 0.39 8.93
0.486 0.154 0.165 0.006 0.003 0.021 0.001 0.023
0.56 0.47 0.45 0.98 0.22 0.98 0.99 0.89
0.52 0.45 0.39 0.97 0.27 0.93 0.98 0.95
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FPS: 100% fine limestone (0.2 mm GMD - geometric mean diameter). PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD. 3 PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD. 4 PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. 5 SEM: standard error of the mean. 6 P: Probability level. 2
Egg specific gravity was not different among the different treatments (P > 0.05). However, the values obtained in the present study were lower than that recommended for optimal hatchability and chick quality, 1.080 g/mL (Ingram et al., 2008), and may increase the embryo mortality (Narushin and Romanov, 2002). In this study the broiler breeders were raised in an opensided house, and although the average temperature was approximately 23.5◦ C during the experimental period, the minimum and the maximum temperatures recorded were 15.4◦ C and 41.9◦ C, respectively. This variation may have been the reason for the lower egg specific gravities observed in this study. Similarly lower values were also observed by Chung et al., (2005) and Ajakaiye et al., (2011), although in normal environmental temperature conditions. The different limestone particle sizes in the diet did not affect (P > 0.05) tibial ash, calcium, or phosphorus contents, neither tibial breaking strength in 82week-old post-molting broiler breeders (Table 4). In addition to being essential for eggshell formation, calcium plays an important role in chicken bone integrity (Moreki et al., 2011). Any deficiency in calcium supply or metabolism results in weaker bones and eggshells (Roberson, 2004). Broiler breeders are submitted to feed restriction regimes, and consume their daily meal in 2 to 4 hours after feed is supplied in the morning. As
RESULTS AND DISCUSSION The dietary inclusion of limestone with different particle sizes did not affect the evaluated performance and egg characteristics of broiler breeders after molting (Table 3). The use of mixtures of limestone with different particle sizes has been suggested as a tool to improve calcium solubility, and therefore, to obtain better egg physical characteristics (Zhang and Coon, 1997; Pizzolante et al., 2006). Rao and Roland (1992) suggest that the partial replacement of fine limestone by coarse limestone in the diet may be beneficial when eggshell thickness problems are observed. However, no changes in egg shape index or eggshell weight, percentage, and thickness (P > 0.05) were observed in the present experiment, as well as in the percentage of cracked or broken eggs as a function of treatments. Eggshell defects reduce fertility and hatchability and increase embryo mortality (Roque and Soares, 1994, Nakage et al., 2002).
Table 4. Post-molting tibial ash and calcium content, breaking strength, and density of broiler breeders fed diets containing limestone with different particles sizes. P6 1
Parameters
FPS
Ashes (%) Calcium (%) Breaking strength (kgf) Density (g/ml)
58.4 23.2 38.8 0.91
1
2
3
4
5
PS1
PS2
PS3
SEM
Linear
Quadratic
58.2 23.3 37.2 0.92
58.8 23.9 34.6 0.86
59.1 23.9 35.6 0.88
0.30 0.16 0.94 0.01
0.67 0.64 0.34 0.80
0.49 0.87 0.43 0.91
FPS: 100% fine limestone (0.2 mm GMD - geometric mean diameter). PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD. 3 PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD. 4 PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. 5 SEM: standard error of the mean. 6 P: Probability level. 2
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Shapiro-Wilk and Bartlett, respectively. Data were then submitted to one-way ANOVA at 5% probability level. Data were subjected to orthogonal polynomial analysis (linear and quadratic trends). Calcium level in the gizzard content was analyzed by the test of Friedman at 95% probability level.
LIMESTONE IN POST MOLTING BROILER BREEDER DIETS
the amount of calcium present in the digestive tract at the time of eggshell deposition, usually during the night, is low, a significant fraction of calcium is removed from the skeleton for eggshell formation. The higher contribution of skeletal calcium for eggshell formation, the worse the eggshell quality (Williams et al., 2000a,b). According to Witt et al. (2009), increasing limestone particle size may improve tibial bone strength in layers, possibly due to bone morphometric characteristics and not to higher calcium deposition, because bone weight does not change. On the other hand, in studies evaluating dietary calcium levels and limestone particle size for commercial layers, Cheng and Coon (1990), and Pelicia et al. (2011) did not observe any effect of limestone particle size on bone quality, only of dietary calcium content. It was expected that increasing dietary limestone particle size would improve the physical-chemical characteristics of the tibiae of the hens as a result of the gradual release of calcium from the gizzard to the small intestine, thereby increasing calcium absorption time and utilization and reducing bone mobilization. However, this was not observed. The analysis of the amount of calcium retained in the gizzard 28 h after feeding (Figure 1) did not show any differences in calcium release to the small intestine as a function of particle size (P > 0.05). These results are different from those reported in studies with commercial layers. For instance, Rao and Roland (1992) and Zhang and Coon (1997) evaluated different dietary limestone particle sizes for white layers (at 79 and 88 weeks of age, respectively), and observed higher calcium retention in the gizzard 4, 12, and 24 hours after feeding as particle size increased. Embryo development, hatchability, and post-hatch growth are not only influenced by incubation conditions, but also by egg characteristics, including egg weight (Dalanezi et al., 2005; Ulmer-Franco et al., 2010). However, in the present experiment, eggs were
submitted to the same incubation management and presented similar weights. The results in Table 5 show that the evaluated treatments had no influence on hatchability, egg weight loss during incubation, or chick quality (P > 0.05). During incubation, egg weight loss by evaporation is controlled by the relative humidity of the incubator and it is influenced by eggshell quality (Peebles et al., 2001; Rosa et al., 2002). Egg weight loss during incubation has been associated with incubation results and used as a tool to evaluate incubation yield (Tullett and Burton, 1993). Higher losses may cause dehydration and high initial embryo mortality, whereas lower losses may promote high late embryo mortality, and the embryos are not able to inflate their lungs due to the excessive amount of water (Santos et al., 2009). Almeida et al. (2006) showed evaporative losses of 14 to 15% in older breeder eggs, because they present thinner eggshells, lower area to volume ratio, and higher water content in the albumen compared with eggs of younger breeders. The egg weight loss in the present experiment was between 10.35% and 10.64%, below that considered as the optimal value (Aviagen, 2010), but embryo mortality and chick yield were not different. Rosa et al. (2002) obtained optimal hatchability when eggs lost 10.3% of their weight, which is consistent with the values obtained in the present study. Chick yield (hatchling weight as a percentage of set egg weight) is a simple method of checking the hatching time, which in turn is influenced by eggshell quality. Yields between 67% and 68% are considered optimal for chick livability and growth, but higher than 68% is considered high and may compromise chick livability during the first week of grow-out (Aviagen, 2010). Neither eggshell quality or chick yield were influenced by the evaluated treatments (P > 0.05) in the present experiment. Despite being higher than 70%, chick quality and first-week performance were not affected. Chick average body weight was evenly distributed at placement (P > 0.05) and no growth potential differences, as measured by weight gain (P > 0.05) during their first seven days of life (pre-starter phase; Table 6), were detected among chicks derived from broiler breeders fed different limestone particle sizes. This result confirms the absence of any influence of the evaluated treatments on eggshell quality, and consequently on chick growth performance. No differences in feed intake and feed conversion ratio were detected either (P > 0.05). Tibial ash and calcium contents of 7-day-old chicks were not affected by the treatments, and ranged between 46.4% and 47.3% and between 17.9% and 18.6%, respectively (P > 0.05). No changes in tibial weight were detected (Table 6). The results of the present experiment indicate that post-molting performance and reproduction parameters of broiler breeders were not influenced by different limestone particle sizes. The dietary inclusion of coarse limestone particles did not affect the post-molting bone
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Figure 1. Calcium level (%) in the gizzard content of broiler breeders determined 8, 10, 12, and 28 hour after the last meal fed with FPS - 100% fine limestone (0.2 mm GMD - geometric mean diameter), PS - 30% fine limestone + 70% limestone with 1.0 mm GMD, PS2 - 30% fine limestone + 70% limestone with 2.0 mm GMD, or PS3 - 30% fine limestone + 70% limestone with 3.0 mm GMD.
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BUENO ET AL. Table 5. Hatchability, egg weight loss, chick yield, and chick quality of second-cycle broiler breeders fed diets containing limestone with different particles sizes. P6 Parameters
FPS1
PS12
PS23
PS34
SEM5
Linear
Quadratic
Egg initial weight (g) Egg weight loss (%) Hatchability (%) First-quality chicks (%) Second-quality chicks (%) Chick yield (%)
71.3 10.6 92.6 89.1 3.47 70.3
71.3 10.3 89.2 86.9 2.55 70.9
71.3 10.6 91.9 89.3 2.78 71.0
71.5 10.5 91.6 88.7 2.49 70.9
0.11 0.12 0.46 0.44 0.22 0.16
0.34 0.74 0.59 0.74 0.46 0.10
0.27 0.73 0.58 0.72 0.55 0.12
1
FPS: 100% fine limestone (0.2 mm GMD - geometric mean diameter). PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD. 3 PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD. 4 PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. 5 SEM: standard error of the mean. 6 P: Probability level. 2
Parameters
FPS1
PS12
PS23
PS34
SEM5
P6
Chick initial weight (g) Body weight (g; d7) Feed intake (g/1 to 7 d) Weight gain (1 to 7 d; g) Feed conversion ratio (g/g) Tibial ashes (%) Tibial Ca (%) Tibial weight (g)
47 195 151 148 1.01 47.3 18.6 212
48 196 148 148 0.99 47.2 18.1 213
48 198 151 150 1.00 46.9 18.2 220
48 197 150 148 1.01 46.4 17.9 211
0.1 0.8 0.8 0.7 0.4 0.135 0.112 0.2
0.2 0.7 0.5 0.7 0.5 0.07 0.1 0.4
1
FPS: 100% fine limestone (0.2 mm GMD - geometric mean diameter). PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD. 3 PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD. 4 PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. 5 SEM: standard error of the mean. 6 P: Probability level. 2
status of broiler breeders or their progenies’ growth potential.
REFERENCES Ajakaiye, A., J. O. Atteh, and S. Leeson. 1997. Effects of calcium source, particle size and time on in vitro calcium solubility of some indigenous Nigerian mineral ingredients for poultry diets. Anim. Feed Sci. Technology Journal. 65:293–298. Ajakaiye, J. J., A. Perez -Bello, and A. Mollineda-Trujillo. 2011. Impact of heat stress on egg quality in layer hens supplemented with l-ascorbic acid and dl-tocopherol acetate. Veterinarski Arhiv. 81:119–132 Al-Batshan, H. A., S. E. Sceideler, B. L. Black, J. D. Garlich, and K. E. Anderson. 1994. Duodenal calcium uptake, femur ash and eggshell quality decline with age and increase following molt. Poult. Sci. 73:1590–1596. Almeida, J. G., F. Dahlke, A. Maiorka, D. E. Faria Filho, and C. A. Oelke. 2006. Efeito da idade da matriz no tempo de eclos˜ ao, tempo de permanˆencia do neonato no nascedouro e peso do pintainho. Arch. Vet. Sci. 11:45–49. Almeida, J. G., S. L. Vieira, R. N. Reis, J. Berres, R. Barros, A. K. Ferreira, and F. V. F. Furtado. 2008. Hatching distribution and embryo mortality of eggs laid by broiler breeders of different ages. Braz. J. Poult. Sci. 10:89–96. Association of Official Analytical Chemists - AOAC. 1995. Official Methods of Analysis. 16.ed. AOAC, Washington, DC. Attia, Y. A., W. H. Burk, and K. A. Yamani. 1994. Response of broiler breeder hens to forced molting by hormonal and dietary manipulations. Poult. Sci. 73:245–258.
AVIAGEN. 2010. How to. . . hatchery. Acessed Sept. 2015. http://en. aviagen.com/assets/Tech Center/BB Resources Tools/Hatchery How Tos/AviagenHatcheryHowToSummary1to10EN15.pdf. Buhr, R. J., and D. L. Cunninghan. 1994. Evaluation of molt induction to body weight loss fifteen or twenty-five percent by feed removal, daily limited, or alternative-day feeding of a molt feed. Poult. Sci. 73:1499–1510. Cheng, T. K., and C. Coon. 1990. Effect of calcium source, particle size, limestone solubility in vitro, and calcium intake level on layer bone status e performance. Poult. Sci. 69:2214–2219. Christensen, V. L., and F. M. McCorkle. 1982. Turkey egg weight loss and embryonic mortality during incubation. Poult. Sci. 61:1209– 1213. Chung, M. K., J. H. Choi, Y. K. Chung, and K. M. Chee. 2005. Effects of Dietary Vitamins C and E on Egg Shell Quality of Broiler Breeder Hens Exposed to Heat Stress. Asian-Aust. J. Anim. Sci. 18:545–551. Cobb-Vantress. 2005. Cobb 500 Breeder Management Guide. Blueprint for Success. Cobb-Vantress, Siloam Springs, AR. Dalanezi, J. A., A. A. Mendes, E. A. Garcia, R. G. Garcia, J. Moreira, and I. C. L. Paz. 2005. Efeito da idade da matriz sobre o desempenho e rendimento de carca¸ca de frangos de corte. Arq. Bras. Med. Vet. Zootec. 57:250–260. Decuypere, E., and G. Verheyen. 1986. Physiological basis of induced moulting and tissue regeneration in fowls. World’s Poult. Sci. J. 42:55–68. Freitas, E. R., N. K. Sakomura, M. M. Gonzalez, and N. A. A. Barbosa. 2004. Compara¸c˜ao de m´etodos de determina¸c˜ao da gravidade espec´ıfica de ovos de poedeiras comerciais. Pesq. Agrop. Brasil. 9:509–512. Hamidu, J. A., Z. Uddin, M. Li, G. M. Fasenko, L. L. Guan, and D. R. Barreda. 2011. Broiler egg storage induces cell death and influences embryo quality. Poult. Sci. 90:1749–1757. Ingram, D. R., L. F. Hatten, and K. D. Homan. 2008. A Study on the Relationship Between Eggshell Color and Eggshell Quality in Commercial broiler breeders. Int. J. Poult. Sci. 7:700–703. Leeson, S., and J. D. Summers. 1997. Commercial poultry nutrition. 2nd ed University Books, Guelph, ON, Canada. Manangi, M. K., and C. N. Coon. 2006. Evaluation of phytase enzyme with chick fed basal diets containing different soybean meal samples. J. Appl Poult. Res. 15:292–306. Moreki, J. C., H. J. Van Der Merwe, and J. P. Hayes. 2011. Influence of dietary calcium levels on bone development in broiler breeder pullets up to 18 weeks of age. Online J. Anim. Feed Res. 1:28–39. Nakage, E. S., J. P. Cardozo, G. T. Pereira, S.A. Queiroz, and I. C. Boleli. 2002. Efeito da forma f´ısica da ra¸c˜ao sobre a porosidade, espessura da casca, perda de ´agua e eclodibilidade em ovos de perdiz (Rhynchotusrufescens). Braz. J. Poult. Sci. 4:227–234. Narushin, V. G., and M. N. Romanov. 2002. Egg physical characteristics and hatchability. World’s Poult. Sci. J. 58:297–303. Peebles, E. D. M. R. Burnham, M. R., and C. W. Gardner. 2001. Effects of incubational humidity and hen age on embryo composition in broiler hatching eggs from young breeders. Poult. Sci. 80:1299–1304.
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Table 6. Pre-starter performance, tibial ash and calcium (Ca) contents, and tibial weight of 7-day-old chicks derived from second-cycle broiler breeders fed diets containing limestone with different particles sizes.
LIMESTONE IN POST MOLTING BROILER BREEDER DIETS
hatchability, and chick body weight from broiler breeders. Poult. Sci. 81:327–332. Tullett, S. G., and F.G. Burton. 1993. Factors affecting the peso e water status of chick at hatch, Br. Poult. Sci. 72:251–258. Ulmer-Franco, A. M., G. M. Fasenko, and E. E. O‘Dea Christopher. 2010. Hatching egg characteristics, chick quality, and broiler performance at 2 breeder flock ages and from 3 egg weights. Poult. Sci. 89:2735–2742. Verheyen, G., and E. Decuypere, 1986. Les r´esultats de production chez des poules reproductrices naines du type chair en fonction de technique d’induction de l’arrˆet de la ponte. Rev. Agric. 39:163– 175. Vieira, S. L., J. G. Almeida, A. R. Lima, O. R. A. Conde, and A. R. Olmos. 2005. Hatching distribution of eggs varying in peso and breeder age. Braz. J. Poult. Sci. 7:73–78. Vieira, S. L., and E. T. Moran, JR. 1998. Comparison of egg and chicken from broiler breeder of extremely different age. J. Appl. Poult. Res. 7:372–376. Vieira, S. L., and E. T. Moran, JR. 1999. Effects of the egg origin and chick post-hatch nutrition on broiler live performance and meat yields. World’s Poult. Sci. J. 55:125–142. Williams, B., D. Waddington, S. Solomon, B. Thorp, and C. Farquharson. 2000a. Skeletal development in the meat-type chicken. Br. Poult. Sci. 41:141–149. Williams, B., S. Solomon, D. Waddington, B. Thorp, and C. Farquharson. 2000b. Dietary effects on bone quality and turnover, and Ca and P metabolism in chickens. Res. Vet. Sci. 69:81–87. Witt, F. H. Kuleile, H. J. Merwe, and V. D. Fair. 2009. Effect of limestone particle size on bone quality characteristics of hens at end-of-lay. World’s Poult. Sci. J. 39:41–44. Zakaria, A. H., P. W. Plumstead, H. Romero-Sanchez, N. Leksrisompong, and J. Brake. 2009. The effects of oviposition time on egg weight loss during storage and incubation, fertility, and hatchability of broiler hatching eggs. Poult. Sci. 88:2712– 2717. Zhang, B., and C. N. Coon. 1997. The relationship of calcium intake, source, size, solubility in vitro in vivo, gizzard limestone retention in laying hens. Poult. Sci. 76:1702–1706.
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Pelicia, K., J. L. M. Mourao, E.A. Garcia, V. M. C. Pinheiro, D. A. Berto, A. B. Molino, A. B. G. Faitarone, F. Vercese, G. C. Santos, and A. P. Silva. 2011. Effects of dietary calcium levels and limestone particle size on the performance, tibia and blood of laying hens. Braz. J. Poult. Sci. 13:29–34. Pizzolante, C. C., E. A. Garcia, C. Lagan´ a, E. S. P. E. Saldanha, A. P. Deodar, M. R. Scherer, and L. Batista. 2006. Effect of the calcium level and limestone particle size on the performance of semi-heavy layers in the second cycle of egg production. Braz. J. Poult. Sci. 8:173–176. Rao, K. S., and D. A. Roland. 1992. Improved limestone retention in the gizzard of commercial leghorn hens. J. Appl. Poult. Res. 1:6–10. Rath, N. C., J. M. Balog, W. W. Huff, G. R. Huff, J. B. Kulkarni, and J. F. Tierce. 1999. Comparative differences in the composition and biomechanical properties of tibiae of seven and seventy-weedold male and female broiler breeder chicks. Poult. Sci. 7:1232– 1239. Rayan, G. N., A. Galal, M. M. Fathi, and A. H. El-Attar. 2010. Impact of layer breeder flock age and strain on mechanical and ultrastructural properties of eggshell in chicken. Int. J. Poult. Sci. 9:139–147. Roberson, K. D. 2004. Estimation of the dietary calcium and non phytate phosphorus needs of growing commercial tom turkeys weighing four to twelve kilograms. Int. J. Poult. Sci. 3:175–178. Roque, L., and M. C. Soares. 1994. Effects of eggshell quality and broiler breeder age on hatchability. Poult. Sci. 73:1838–1845. Rosa, P. S., A. L. Guidoni, and I. L. Lima. 2002. Influˆencia da temperatura de incuba¸c˜ao em ovos de matrizes de corte com diferentes idades e classificados por peso sobre os resultados de incuba¸c˜ao. Rev. Bras. Zootec. 31:1011–1016. Santos, J. E. C., F. S. G. Gomes, G. L. F. N. Borges, P. L. S. Silva, E. J. Campos, E. A. Fernandes, and E. C. Guimar˜ aes. 2009. Efeito da linhagem e da idade das matrizes na perda de peso dos ovos e no peso embrion´ ario durante a incuba¸c˜ao artificial. Biosci. J. 25:163–169. Tona, K., F. Bamelis, B. De Ketelaere, V. Bruggeman, and E. Decuypere. 2002. Effect of induced molting on albumen quality,
7
Department of Animal Science, Federal University of Paran´ a, Curitiba, PR, Brazil; and † Laborat´ orio de Avicultura, Department of Animal Science, Federal University of Santa Catarina, Florian´ opolis, SC, Brazil
Key words: broiler breeder, calcium, egg quality, incubation 2016 Poultry Science 0:1–7 http://dx.doi.org/10.3382/ps/pev438
INTRODUCTION
(Al-Batshan, et al. 1994; Rayan et al., 2010). Eggshell porosity and thickness strongly influence embryo development and hatchling quality (Narushin and Romanov, 2002). The production of good-quality hatchlings requires eggs to present more than 1.080 egg specific gravity (Roque and Soares, 1994; Narushin and Romanov, 2002). Induced molting is a commercial practice that aims at improving the reproductive performance of broiler breeders and at restoring egg quality (Verheyen and Decuypere, 1986; Buhr and Cunninghan, 1994; Tona et al., 2002). Many studies have reported that eggshell and albumen quality, hatchability, and juvenile growth performance are positively influenced by molting (Decuypere and Verheyen, 1986; Attia et al., 1994; Tona et al., 2002). Relative hatchling weight (hatchling weight to egg weight ratio) is higher after than before molting in mature broiler breeders (Tona et al., 2002), and the eggs of molted hens lose less weight during incubation, possibly due to better eggshell structural characteristics (Christensen and McCorkle, 1982). Calcium solubility in layers is influenced by several factors, including calcium source, particle size, time of retention in the gizzard, and interaction with other feedstuffs (Ajakaiye et al., 1997). Studies with layers
Many factors affect the chick embryo and consequently hatchling quality and broiler growth potential, including egg storage, duration of incubation, and breeder age (Almeida et al., 2008; Hamidu et al., 2011). Previous studies have determined that egg weight (Ulmer-Franco et al., 2010) and hatchling weight (Vieira et al., 2005) increase as broiler breeders age. In addition, albumen characteristics, albumen/yolk ratio, embryo survival, and hatchability are also influenced by broiler breeder age (Vieira and Moran, 1998, 1999). According to Zakaria et al. (2009) weight loss is higher in eggs of older breeders’ as compared with those of younger breeders, and may be ascribed to the deterioration of eggshell quality. This is a result of the accumulation of fat in the uterus, which impairs calcium deposition in the eggshell, intestinal calcium absorption, and calcium release from the bloodstream, resulting in increasingly thinner eggshells as breeder’s age C 2016 Poultry Science Association Inc. Received May 29, 2015. Accepted November 13, 2015. 1 Corresponding author: [email protected]
1
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teristics, and breeder performance, egg characteristics, eggshell quality, incubation performance, chick quality and yield, chick pre-starter live performance, and chick bone characteristics were determined. There was no significant difference (P > 0.05) in the rate of lay, percentage of non-settable eggs, egg weight, egg shape index, egg specific gravity, eggshell weight, thickness, and percentage hatchability and egg weight loss of broiler breeders fed with diets with different limestone particle sizes. The chick quality and yield, chick pre-starter live performance, and chick bone characteristics were not affected (P > 0.05) by any of the limestone particle sizes. It was concluded that live and reproductive performance parameters of broiler breeders post molting is not affected by limestone particle size in the feed.
ABSTRACT An experiment was conducted to test the hypothesis that a coarse limestone diet improves productivity, reproductive performance and the calcium utilization of molted broiler breeders. In total, 640 broiler breeder females, 73-week-old and sixty-four 27-week-old cockerels, Cobb 500, were evaluated during 10 weeks, according to a randomized block design composed of 4 treatments with 8 replicates each. Treatments consisted of diets with the inclusion of 100% fine limestone - fine PS (0.2 mm GMD - geometric mean diameter); PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD; PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD; and PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. Calcium retention in the gizzard of the breeders, bone charac-
2
BUENO ET AL.
have reported long gizzard retention times of large particles of limestone, which release calcium slowly and uniformly during the period of eggshell formation (Zhang and Coon, 1997; Leeson and Summers, 1997), thereby allowing the retention of calcium in the medullary bones of the birds (Rao and Roland, 1992). Manangi and Coon (2006) observed the dietary inclusion of limestone with larger particles reduced phosphorus excretion and improved egg specific gravity, which is an eggshell quality measurement. The objective of the present study was to compare the dietary inclusion of limestone with different particle sizes on the live performance of broiler breeders, eggshell quality, parental and progeny skeletal structure, and broiler performance.
The experiment was approved by the Ethics Commission for Experimental Use of Animals of the Federal University of Paran´ a, Brazil (0431/2011). A commercial flock of Cobb 500 broiler breeders (640 females and 64 males) was utilized. Before the experimental period, all birds were submitted to the same management practices, following the Cobb 500 Breeder Management Guide (Cobb-Vantress, 2005). At 22 weeks of age the flock was transferred to a production house (open-side house), where they remained up to 63 weeks of age. The females were submitted to the traditional system of induced molting at 65 weeks of age, and then transferred to the experimental house at 73 weeks of age and distributed in 32 pens, measuring 12.0 m2 each (3.0 × 4.0 m). The experimental house was open-sided with fibrocement roof and polypropylene side curtains, and had a concrete floor covered with new wood-shaving litter. The house was equipped with trough feeders for females, tube feeders for males, nipple drinkers, and nests for manual egg collection. Artificial light was supplied by incandescent lamps. Birds were individually weighed and distributed to the pens according to 2 weight classes: light (2.5 to 3.0 kg) or heavy (3.1 to 3.5 kg) in order to obtain homogenous experimental units. Sixty-four 27-week-old cockerels (3.700 ± 0.050 kg) were housed with the females. During the experimental period, eggs were collected five times daily (08:00, 10:30, 13:00, 15:30, and 17:30 h) and classified as settable or non-settable (cracked/broken) eggs.
Experimental Design and Diets The chicks were randomly allocated into 4 dietary treatments, and each treatment had 8 replicates with 20 hens and 2 cockerels per experimental unit. Birds were distributed in a randomized complete block design where weight class was the criterion for the establishment of the blocks. The experimental treatments consisted of diets containing limestone with different
Ingredients (%)
FPS1
PS12
PS23
PS34
Corn Soybean meal 46% CP Limestone Kaolin Dicalcium phosphate Soybean oil Vitamin and mineral5 supplement1 Sodium chloride Sodium bicarbonate DL-methionine Choline chloride L-lysine
66.4 22.4 6.60 1.70 1.20 0.50 0.40 0.29 0.20 0.14 0.09 0.03
66.4 22.4 6.60 1.70 1.20 0.50 0.40 0.29 0.20 0.14 0.09 0.03
66.4 22.4 6.60 1.70 1.20 0.50 0.40 0.29 0.20 0.14 0.09 0.03
66.4 22.4 6.60 1.70 1.20 0.50 0.40 0.29 0.20 0.14 0.09 0.03
Determined chemical composition Moisture (%) 11.49 Crude protein (%) 15.12 Calcium (%) 3.08 Ash (%) 13.69 Total phosphorus (%) 0.50
11.59 15.11 3.02 13.07 0.49
11.60 15.04 3.10 13.43 0.49
11.64 15.11 3.13 13.28 0.50
(on as-fed basis) 2,85 2,85 2,85 0.42 0.42 0.42 0.18 0.18 0.18 0.71 0.71 0.71 0.35 0.35 0.35 0.16 0.16 0.16
2,85 0.42 0.18 0.71 0.35 0.16
Calculated chemical composition Metabolizable energy (kcal/kg) Available phosphorus (%) Sodium (%) Digestible lysine (%) Digestible methionine (%) Digestible tryptophan (%)
1 FPS: 100% fine limestone (0.2 mm GMD - geometric mean diameter). 2 PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD. 3 PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD. 4 PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. 5 Levels supplied/kg of diet: vitamin A 12,200 UI; vitamin D3 3,700 UI; vitamin E 21.6 UI; vitamin K3 2.9 UI; vitamin B1 3.2 mg; vitamin B2 12.6 mg; vitamin B6 5.5 mg; vitamin B12 0.046 mg; pantothenic acid 20 mg; niacin 40 mg; folic acid 4 mg; biotin 0.29 mg; selenium 0.20 mg; copper 20 mg; iron 50 mg; manganese 115 mg; zinc 100 mg; iodine 2 mg.
Table 2. Limestone geometric mean diameter (GMD), geometric standard deviation (GSD), and calcium content. Parameters Limestone Limestone Limestone Limestone
0.2 1.0 2.0 3.0
GMD GMD GMD GMD
GMD mm
GSD %
Ca %
0.23 1.13 1.91 2.92
1.11 1.42 1.19 1.32
38.2 38.2 38.2 38.2
particle sizes, as determined by geometric mean diameter (GMD): fine particle size (FPS), with 100% fineparticle limestone (GMD of 0.2 mm); 1.0 mm particle size (PS1) with 30% fine limestone and 70% limestone with 1.0 mm GMD; 2.0 mm particle size (PS2), with 30% fine limestone and 70% limestone with 2.0 mm GMD; and 3.0 mm particle size (PS3), with 30% fine limestone and 70% limestone with 3.0 mm GMD. Feeds was in mash form and formulated on a corn and soybean meal basis (Table 1). All diets contained equal calcium and limestone levels. Limestone was analyzed for GMD, particle-size distribution (geometric standard deviation – GSD), and calcium content (Table 2). Females in all treatments were offered the same amount of feed calculated according to egg production (5% production – 130 g ration; 10% - 133 g; 20% - 136 g; 30%
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MATERIAL AND METHODS
Table 1. Composition and nutritional levels of the experimental diets.
LIMESTONE IN POST MOLTING BROILER BREEDER DIETS
- 140 g; 40% - 146 g; 50% - 152 g; 60% - 158 g; > 70% - 164 g), which was measured weekly. Males were fed according to their body condition score, which was evaluated weekly. Feed was supplied in the morning. Water was offered ad libitum.
Measured Parameters
Hatching rate was calculated as the ratio between viable hatchlings and the total number of incubated eggs. Hatch yield was calculated as the ratio between egg weight at setting and hatchling weight. In order to evaluate fertility and embryo mortality, non-hatched eggs were counted and submitted to embryo diagnosis. In total, 1,456 good quality chicks (364 per treatment) were reared in different pens in an experimental broiler house at a density of 12 chicks/m2 at 30 to 32◦ C until 7 days old, and live performance (feed intake, weight gain, and feed conversion ratio) was evaluated. Chicks were housed according to their breeder’s treatment, totaling 14 replicates with 26 birds each. A photoperiod of 22 h of light and 1 h of dark was applied. Birds were fed a standard broiler pre-starter diet (3,000 kcal metabolizable energy/kg, 23.00% crude protein) ad libitum. At the end of the experimental phase, 3 chicks per replicate were sacrificed by neck dislocation and the right tibiae were collected for the determination of calcium and ash contents. When hens were 83 weeks old, 8 hens per treatment were sacrificed after 8, 10, 12, and 28 hours of feed fasting. The digestive tract was collected, and gizzard content was removed, weighed, and dried in a forcedventilation oven (16 h at 105◦ C). Gizzard content was analyzed for dry matter, calcium, and ash contents (AOAC, 1995) in order to estimate calcium (limestone) retention percentage in the gizzard at different times after feeding. Both tibiae were collected: the left tibiae was used to measure bone density and breaking strength, whereas the right tibiae was analyzed for ash and calcium contents. The left tibia was cooked in boiling water for one minute to remove meat, proximal cartilage, and the fibula, and then immersed in ethylic ether for 24 h for the complete removal of fat residues. After complete ether evaporation, bones were dried in an oven at 65 ◦ C for 24 h, weighed, and placed in a muffle at 600◦ C for subsequent determination of bone ash and calcium contents (AOAC, 1995). The right tibiae were subjected to the same procedure of meat, cartilage, and fat removal. After drying, tibiae were weighed (Tecnal, model BG – 400, Piracicaba, Brazil), and their length was measured using a digital caliper. To determine bone density, Archimedes’ principle was applied (Rath et al., 1999). After that, bones were dried again in an oven (65◦ C for 24 h) and their breaking strength was determined by applying a perpendicular force at the speed of 5 mm/min with a 30 mm diameter cylindrical knife at the midpoint between epiphyses (EMIC apparatus, model DL2000, INSTRON, Paran´ a, Brazil). Bone breaking strength was determined as the maximum strength required to break the bone completely.
Statistical Analysis The assumptions of residue normality and homoscedasticity were analyzed by the tests of
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Rate of lay was evaluated between weeks 74 and 83. This was calculated as the ratio between total egg production and number of hens, and expressed as a percentage. The percentage of non-settable (cracked or broken) eggs relative to total egg production was also evaluated. Egg characteristics (weight and egg shape index) and eggshell quality (egg specific gravity, eggshell absolute weight, eggshell weight relative to total egg weight, and eggshell thickness) were determined twice weekly between weeks 74 and 77 in all eggs produced on the day of evaluation. Egg specific gravity was determined using the flotation method (Freitas et al. 2004). Egg shape index was determined by measuring intact egg width and length with a digital caliper (Lee Tools, model 684132, S˜ ao Paulo, Brazil) for the calculation of width to length ratio. For the determination of eggshell parameters, eggs were individually identified and broken. Eggshells were washed under running water and dried in an oven at 35o C for 15 hours. Eggshells were then weighed and their relative weight calculated. Eggshell thickness was measured at 3 different regions with the digital caliper to calculate average eggshell thickness. Both eggs and eggshells were weighed in a digital precision scale (0.001 g). Incubation responses were evaluated using the eggs laid between weeks 78 and 79. The eggs were collected, disinfected, and individually weighed and identified. Until setting, eggs were stored for a maximum period of 7 days in an environmentally controlled room (19 to 21◦ C and 60 to 80% RH). Six trays of 96 eggs were incubated per treatment (one tray per replicate). Eggs were incubated in a CASP machine (model Mg124, CASP, Amparo, SP, Brazil) at 37.5o C (99.5 Fo ) and 52.5% RH in trays identified per replicate and randomly distributed in the incubation trolleys. On d 18, eggs were transferred to a CASP Hatcher (model Ug21, CASP, Amparo, SP, Brazil) at 36.5◦ C and 65% RH until hatch. Egg trays were weighed empty and with the eggs before being placed in the incubator and at the time of transfer to the hatcher in order to determine egg weight loss during incubation. Hatchlings were removed from the hatcher, counted, and weighed at the 504th incubation hour. Each hatchling was visually examined and classified as a first- or second-quality chick. First-quality chicks were defined as clean, dry, free from contamination, free of deformities (no skin lesions, well-formed beak, good leg conformation), and with the navel completely closed, with no yolk sac or dried membranes protruding from the navel.
3
4
BUENO ET AL. Table 3. Post-molting rate of lay and egg characteristics of broiler breeders fed diets containing limestone with different particles sizes. P6 Parameters
FPS1
PS12
PS23
PS34
SEM5
Linear
Quadratic
Rate of lay (%) Cracked/broken eggs (%) Egg weight (g) Egg shape index Egg specific gravity (g/ml) Eggshell weight (g) Eggshell thickness (mm) Eggshell (%)
69.8 5.26 71.0 0.73 1.07 6.36 0.39 8.95
72.4 5.80 71.0 0.73 1.06 6.39 0.39 8.99
69.9 5.38 71.2 0.73 1.06 6.31 0.39 8.88
69.5 5.26 70.5 0.73 1.06 6.33 0.39 8.93
0.486 0.154 0.165 0.006 0.003 0.021 0.001 0.023
0.56 0.47 0.45 0.98 0.22 0.98 0.99 0.89
0.52 0.45 0.39 0.97 0.27 0.93 0.98 0.95
1
FPS: 100% fine limestone (0.2 mm GMD - geometric mean diameter). PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD. 3 PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD. 4 PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. 5 SEM: standard error of the mean. 6 P: Probability level. 2
Egg specific gravity was not different among the different treatments (P > 0.05). However, the values obtained in the present study were lower than that recommended for optimal hatchability and chick quality, 1.080 g/mL (Ingram et al., 2008), and may increase the embryo mortality (Narushin and Romanov, 2002). In this study the broiler breeders were raised in an opensided house, and although the average temperature was approximately 23.5◦ C during the experimental period, the minimum and the maximum temperatures recorded were 15.4◦ C and 41.9◦ C, respectively. This variation may have been the reason for the lower egg specific gravities observed in this study. Similarly lower values were also observed by Chung et al., (2005) and Ajakaiye et al., (2011), although in normal environmental temperature conditions. The different limestone particle sizes in the diet did not affect (P > 0.05) tibial ash, calcium, or phosphorus contents, neither tibial breaking strength in 82week-old post-molting broiler breeders (Table 4). In addition to being essential for eggshell formation, calcium plays an important role in chicken bone integrity (Moreki et al., 2011). Any deficiency in calcium supply or metabolism results in weaker bones and eggshells (Roberson, 2004). Broiler breeders are submitted to feed restriction regimes, and consume their daily meal in 2 to 4 hours after feed is supplied in the morning. As
RESULTS AND DISCUSSION The dietary inclusion of limestone with different particle sizes did not affect the evaluated performance and egg characteristics of broiler breeders after molting (Table 3). The use of mixtures of limestone with different particle sizes has been suggested as a tool to improve calcium solubility, and therefore, to obtain better egg physical characteristics (Zhang and Coon, 1997; Pizzolante et al., 2006). Rao and Roland (1992) suggest that the partial replacement of fine limestone by coarse limestone in the diet may be beneficial when eggshell thickness problems are observed. However, no changes in egg shape index or eggshell weight, percentage, and thickness (P > 0.05) were observed in the present experiment, as well as in the percentage of cracked or broken eggs as a function of treatments. Eggshell defects reduce fertility and hatchability and increase embryo mortality (Roque and Soares, 1994, Nakage et al., 2002).
Table 4. Post-molting tibial ash and calcium content, breaking strength, and density of broiler breeders fed diets containing limestone with different particles sizes. P6 1
Parameters
FPS
Ashes (%) Calcium (%) Breaking strength (kgf) Density (g/ml)
58.4 23.2 38.8 0.91
1
2
3
4
5
PS1
PS2
PS3
SEM
Linear
Quadratic
58.2 23.3 37.2 0.92
58.8 23.9 34.6 0.86
59.1 23.9 35.6 0.88
0.30 0.16 0.94 0.01
0.67 0.64 0.34 0.80
0.49 0.87 0.43 0.91
FPS: 100% fine limestone (0.2 mm GMD - geometric mean diameter). PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD. 3 PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD. 4 PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. 5 SEM: standard error of the mean. 6 P: Probability level. 2
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Shapiro-Wilk and Bartlett, respectively. Data were then submitted to one-way ANOVA at 5% probability level. Data were subjected to orthogonal polynomial analysis (linear and quadratic trends). Calcium level in the gizzard content was analyzed by the test of Friedman at 95% probability level.
LIMESTONE IN POST MOLTING BROILER BREEDER DIETS
the amount of calcium present in the digestive tract at the time of eggshell deposition, usually during the night, is low, a significant fraction of calcium is removed from the skeleton for eggshell formation. The higher contribution of skeletal calcium for eggshell formation, the worse the eggshell quality (Williams et al., 2000a,b). According to Witt et al. (2009), increasing limestone particle size may improve tibial bone strength in layers, possibly due to bone morphometric characteristics and not to higher calcium deposition, because bone weight does not change. On the other hand, in studies evaluating dietary calcium levels and limestone particle size for commercial layers, Cheng and Coon (1990), and Pelicia et al. (2011) did not observe any effect of limestone particle size on bone quality, only of dietary calcium content. It was expected that increasing dietary limestone particle size would improve the physical-chemical characteristics of the tibiae of the hens as a result of the gradual release of calcium from the gizzard to the small intestine, thereby increasing calcium absorption time and utilization and reducing bone mobilization. However, this was not observed. The analysis of the amount of calcium retained in the gizzard 28 h after feeding (Figure 1) did not show any differences in calcium release to the small intestine as a function of particle size (P > 0.05). These results are different from those reported in studies with commercial layers. For instance, Rao and Roland (1992) and Zhang and Coon (1997) evaluated different dietary limestone particle sizes for white layers (at 79 and 88 weeks of age, respectively), and observed higher calcium retention in the gizzard 4, 12, and 24 hours after feeding as particle size increased. Embryo development, hatchability, and post-hatch growth are not only influenced by incubation conditions, but also by egg characteristics, including egg weight (Dalanezi et al., 2005; Ulmer-Franco et al., 2010). However, in the present experiment, eggs were
submitted to the same incubation management and presented similar weights. The results in Table 5 show that the evaluated treatments had no influence on hatchability, egg weight loss during incubation, or chick quality (P > 0.05). During incubation, egg weight loss by evaporation is controlled by the relative humidity of the incubator and it is influenced by eggshell quality (Peebles et al., 2001; Rosa et al., 2002). Egg weight loss during incubation has been associated with incubation results and used as a tool to evaluate incubation yield (Tullett and Burton, 1993). Higher losses may cause dehydration and high initial embryo mortality, whereas lower losses may promote high late embryo mortality, and the embryos are not able to inflate their lungs due to the excessive amount of water (Santos et al., 2009). Almeida et al. (2006) showed evaporative losses of 14 to 15% in older breeder eggs, because they present thinner eggshells, lower area to volume ratio, and higher water content in the albumen compared with eggs of younger breeders. The egg weight loss in the present experiment was between 10.35% and 10.64%, below that considered as the optimal value (Aviagen, 2010), but embryo mortality and chick yield were not different. Rosa et al. (2002) obtained optimal hatchability when eggs lost 10.3% of their weight, which is consistent with the values obtained in the present study. Chick yield (hatchling weight as a percentage of set egg weight) is a simple method of checking the hatching time, which in turn is influenced by eggshell quality. Yields between 67% and 68% are considered optimal for chick livability and growth, but higher than 68% is considered high and may compromise chick livability during the first week of grow-out (Aviagen, 2010). Neither eggshell quality or chick yield were influenced by the evaluated treatments (P > 0.05) in the present experiment. Despite being higher than 70%, chick quality and first-week performance were not affected. Chick average body weight was evenly distributed at placement (P > 0.05) and no growth potential differences, as measured by weight gain (P > 0.05) during their first seven days of life (pre-starter phase; Table 6), were detected among chicks derived from broiler breeders fed different limestone particle sizes. This result confirms the absence of any influence of the evaluated treatments on eggshell quality, and consequently on chick growth performance. No differences in feed intake and feed conversion ratio were detected either (P > 0.05). Tibial ash and calcium contents of 7-day-old chicks were not affected by the treatments, and ranged between 46.4% and 47.3% and between 17.9% and 18.6%, respectively (P > 0.05). No changes in tibial weight were detected (Table 6). The results of the present experiment indicate that post-molting performance and reproduction parameters of broiler breeders were not influenced by different limestone particle sizes. The dietary inclusion of coarse limestone particles did not affect the post-molting bone
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Figure 1. Calcium level (%) in the gizzard content of broiler breeders determined 8, 10, 12, and 28 hour after the last meal fed with FPS - 100% fine limestone (0.2 mm GMD - geometric mean diameter), PS - 30% fine limestone + 70% limestone with 1.0 mm GMD, PS2 - 30% fine limestone + 70% limestone with 2.0 mm GMD, or PS3 - 30% fine limestone + 70% limestone with 3.0 mm GMD.
5
6
BUENO ET AL. Table 5. Hatchability, egg weight loss, chick yield, and chick quality of second-cycle broiler breeders fed diets containing limestone with different particles sizes. P6 Parameters
FPS1
PS12
PS23
PS34
SEM5
Linear
Quadratic
Egg initial weight (g) Egg weight loss (%) Hatchability (%) First-quality chicks (%) Second-quality chicks (%) Chick yield (%)
71.3 10.6 92.6 89.1 3.47 70.3
71.3 10.3 89.2 86.9 2.55 70.9
71.3 10.6 91.9 89.3 2.78 71.0
71.5 10.5 91.6 88.7 2.49 70.9
0.11 0.12 0.46 0.44 0.22 0.16
0.34 0.74 0.59 0.74 0.46 0.10
0.27 0.73 0.58 0.72 0.55 0.12
1
FPS: 100% fine limestone (0.2 mm GMD - geometric mean diameter). PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD. 3 PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD. 4 PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. 5 SEM: standard error of the mean. 6 P: Probability level. 2
Parameters
FPS1
PS12
PS23
PS34
SEM5
P6
Chick initial weight (g) Body weight (g; d7) Feed intake (g/1 to 7 d) Weight gain (1 to 7 d; g) Feed conversion ratio (g/g) Tibial ashes (%) Tibial Ca (%) Tibial weight (g)
47 195 151 148 1.01 47.3 18.6 212
48 196 148 148 0.99 47.2 18.1 213
48 198 151 150 1.00 46.9 18.2 220
48 197 150 148 1.01 46.4 17.9 211
0.1 0.8 0.8 0.7 0.4 0.135 0.112 0.2
0.2 0.7 0.5 0.7 0.5 0.07 0.1 0.4
1
FPS: 100% fine limestone (0.2 mm GMD - geometric mean diameter). PS1: 30% fine limestone + 70% limestone with 1.0 mm GMD. 3 PS2: 30% fine limestone + 70% limestone with 2.0 mm GMD. 4 PS3: 30% fine limestone + 70% limestone with 3.0 mm GMD. 5 SEM: standard error of the mean. 6 P: Probability level. 2
status of broiler breeders or their progenies’ growth potential.
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Table 6. Pre-starter performance, tibial ash and calcium (Ca) contents, and tibial weight of 7-day-old chicks derived from second-cycle broiler breeders fed diets containing limestone with different particles sizes.
LIMESTONE IN POST MOLTING BROILER BREEDER DIETS
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