Performance of feathered-neck, gray master hillbilly chickens fed various energy levels in the grow out phase^

Introduction

The production of chickens using alternative systems has shown an important growth in recent years due to the interest of a consumer segment for meat with different traits from those of conventionally-farmed broilers (Dourado et al., 2008). Hick-type birds have a darker, firmer, tastier meat, with less carcass fat (Takahashi et al., 2006).

With the introduction of high-yield broiler strains in the Brazilian market, the sector has adopted novel management/nutrition criteria aiming to maximize productivity and optimize the cost. This is why defining optimum energy levels in the feed have become a fundamental aspect, since current broiler genotypes have specific nutritional requirements different from those in the past (Mendes et al. 2004).

Knowing chicken performance is important for producers to plan direct and indirect matters related with population density, feed purchases, market age, etc. The information regarding growth, performance, and carcass yield/quality in these slow-growing chicken strains is fundamental for maximum productivity under such production systems (Dourado et al., 2008).

Research is now focusing better options for alternative energy and protein sources resulting in good productive/reproductive performance, with decreased feeding cost and increased profits (Nascimento et al., 2005). The objective of this study was to evaluate the performance of feathered-neck, Gray Master Hillbilly (French Exotic) in the grow out phase, from 29 to 91 days of age, fed various levels of energy.

Materials and Methods

The study was conducted in an experimental house located in Parauapebas Exposition Park, State of Pará, Brazil. One hundred and nine two (195) feathered-neck, Gray Master Hillbilly (French Exotic), both sexes, one-day-old chickens were reared under an intensive farming system.

The experimental design was completely at random, with 3 treatments and 4 repetitions each. Treatments (T) included various energy levels during the grow out phase (29-91 days of age) as follows: T1: 3,100 Kcal ME/Kg; T2: 3,200 Kcal ME/Kg; T3: 3,300 Kcal ME/Kg. Feeds were prepared using conventional ingredients including corn, soybean meal, soybean oil, meat meal, limestone, dicalcium phosphate, salt, and a vitamin/mineral premix. Formulation calculations were based on the SuperCrac software (2008) in an attempt to meet the nutrient requirements of these birds (Table 1).

Table 1. % Composition and calculated analysis of feeds during the grow out phase

Ingredients	T-1	T-2	T-3
Corn	63.24	60.95	58.66
Soybean meal	27.20	27.60	27.90
Plant oil	2.60	4.50	6.40
Meat meal	5.70	5.70	5.80
Limestone	0.36	0.35	0.34
Salt	0.30	0.30	0.30
Mineral/vitamin premix*	0.60	0.60	0.60
Total	100.00	100.00	100.00
Calculated analysis
ME Kcal/Kg	3.100	3.200	3.300
Crude protein, %	20.00	20.00	20.00
Ether extract, %	5.83	7.64	9.45
Crude fiber, %	3.29	3.27	3.24
Mineral matter, %	5.08	5.08	5.08
Lysine, %	1.07	1.08	1.08
Calcium, %	1.00	1.00	1.00
Total phosphorus, %	0.67	0.66	0.66
Available phosphorus, %	0.48	0.48	0.48
Sodium, %	0.17	0.17	0.17

^{(*) Composition per Kg product: Vit. A - 1,335,000 IU; Vit. D3 - 300,000 IU; Vit. E - 2,000 mg; Vit. B1 - 167 mg; Vit. B2 - 670 mg; Vit. B6 - 170 mg; Vit. K3 - 335 mg; Vit. B12 - 1,670 μg; Biotin - 7 mg; Folic acid - 67 mg; Niacin - 4,670 mg; Selenium - 35 mg; Antioxidant - 2,000 mg; Calcium pantontenate - 1,870 mg; Copper - 1,000 mg; Cobalt - 17 mg; Iodine - 170 mg; Iron 8,335 mg; Manganese - 10,835 mg; Zinc - 7,500 mg; Choline chloride 50% - 83,340; Methionine- 235.000 mg; Coccidiostat - 10,000 mg; Growth promoter - 10,000.}

At facility arrival, the chickens were selected and weighed in order to form homogeneous lots of 16 birds each, then distributed at random among the pens, as per the identification of treatments and repetitions. Water was provided ad libitum. Drinkers were washed and refilled twice per day in order to avoid water intake decreases then feed intake decreases. The feed was weighed once per week and given ad libitum. Feed was present in the feeders at all times. Twice per day, feed in the feeders was mixed as to stimulate feed intake and, in addition, any letter particles were removed.

Variables studied included start weight, end weight, daily feed intake (DFI), feed conversion rate (FCR), protein efficiency, and energy efficiency. Results were statistically analyzed using the ANOVA procedure for a completely-at-random model, with the "Statistical and Genetic Analysis System (SAEG, 2007) software. Mean differences were compared using Tukey´s test, at the 5% level.

Results and Discussion

Dietary energy levels did not influence end weight, FI, DWG, or FCR (Table 2). Filho et al. (2003) found different results with the ESALQ, naked neck Piracicaba, Red Label (Label Rouge) and Stone Gray Paradise (Paraíso Pedrés) strains with feeds containing 3,000 and 3,150 Kcal ME/Kg, with a significant effect on mean DWG, FI, and FCR.

Table 2. Performance of feathered-neck, Gray Master Hillbilly (French Exotic) chickens fed various ME levels in the grow out phase (from 29 to 90 days of age)

Treatments	End weight (g)	Feed intake (g)	Weight gain (g/bird/day)	Feed Conversion Rate
T1 - 3,100 Kcal ME/Kg	3,493.25	6,228.25	45.67	2.16
T2 - 3,200 Kcal ME/Kg	3,455.25	5,944.75	44.44	2.12
T3 - 3,300 Kcal ME/Kg	3,658.75	6,433.50	46.75	2.19
CV (%)	5.38	8.48	6.55	6.36

^{The means show no statistically significant differences, as per Tukey''''s test (P>0.05).}

Dietary energy levels did not influence significantly crude protein intake, ME intake, energy efficiency or protein efficiency (Table 3).

Sakomura et al. (2004) found divergent results when using levels of 3,050, 3,200 and 3,350 Kcal ME/Kg in broiler feeds, where the level of 3,200 Kcal ME/Kg resulted in improved efficiency in the utilization of both energy and protein.

Table 3. Energy and protein efficiency of feathered-neck, Gray Master Hillbilly (French Exotic) chickens during the grow out phase (from 29 to 91 days of age)

Variables	Treatments
T1 3,100 Kcal ME/Kg	T2 3,200 Kcal ME/Kg	T3 3,300 Kcal ME/Kg	CV (%)
Crude protein intake (Kg/bird)	19.77	18.87	20.43	8.48
Me intake (g/bird)	306.47	301.96	336.99	8.38
Protein efficiency	0.43	0.42	0.44	6.36
Energy efficiency	0.15	0.15	0.14	6.42

^{The means show no statistically significant differences, as per Tukey''''s test (P>0.05).}

Conclusions

Dietary Me levels exerted no significant influence on the performance of feathered-neck, Gray Master Hillbilly (French Exotic) chickens during the grow out phase, from 29 to 91 days of age.

Bibliography

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EM Lima^1*, MSV Santos², SS Vieira³, FB Tavares⁴, PA Andrade¹, CS Aguiar¹^Project Financed by Pará State Research Protection Foundation ( FAPESPA);¹Academicians, Animal Husbandry Graduate Course, Federal Rural University of Amazonia, Parauapebas Campus, Brazil; ²Professor Animal Husbandry Graduate Course, Federal Rural University of Amazonia, Parauapebas Campus, Brazil; ³Scholarship Holder, Pibic/CNPq/UFRA; ⁴Masters Undergraduate, Amazonia''''s Animal Health and Production, Animal Husbandry Professional, Federal Rural University of Amazonia, Parauapebas Campus, Brazil.