Effects of low-protein diets on growth performance and carcass yields of growing French meat quails (France coturnix coturnix)

Effects of low-protein diets on growth performance and carcass yields of growing French meat quails (France coturnix coturnix) Z. G. Wen,∗ Y. K. Du,∗ M. Xie,† X. M. Li,∗ J. D. Wang,‡ and P. L. Yang∗,1 ∗

Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed research institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; † Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China; and ‡ Beijing Institute of feed control, Beijing 100107, China

Key words: quails, protein, growth performance, carcass yield 2016 Poultry Science 0:1–6 http://dx.doi.org/10.3382/ps/pew321

INTRODUCTION

ing. It was also unknown whether protein recommendations of NRC (1994) were suitable for modern quail strains. Furthermore, due to severe environmental pollution from ammonia emission and nitrogen excretion of poultry industry, low-protein diets became a valid nutritional strategy to reduce these pollutions. In broilers, with supplementation of crystalline amino acids, a marginal reduction in dietary protein had no negative effect on growth performance and carcass traits and resulted in substantial reduction in nitrogen excretion and ammonia emission into the environment (Namroud et al., 2008; Ospina-Rojas et al., 2014). In growing Muscovy ducks from 8 to 12 weeks of age, no significant modification in growth performance or carcass quality was observed when dietary CP was reduced from 160 g/kg to 124 g/kg in diets based on similar digestible amino acid profile including lysine (Lys), methionine (Met), threonine (Thr), and tryptophan (Trp) (Baeza and Leclercq, 1998). Recently, in growing bobwhite quails from 1 to 56 d of age, the effects of different dietary CP levels (26, 24, 22, and 20%) on growth performance of the birds were examined by Blake and Hess (2013). The results indicated that bobwhite quail appeared to be unaffected by major dietary changes in

Quails are a valuable poultry for the high nutritional value of the eggs and meat. It has the characteristics of early sexual maturity, high egg production, and small body size, which result in lower necessity of housing space and feed. Based on these advantages, the number of quails is gradually expanding in the world. However, limited information exists concerning the nutrient requirements for the rearing of quails. Some of the early studies have investigated protein and amino acid requirements of the quails and have stated a relatively high requirement for protein (28%) in growing bobwhite quails (Baldini et al., 1950; Andrews et al., 1973). The NRC (1994) recommendations of crude protein (CP) were also very high, at 26% for growing bobwhite quails and 24% for growing Japanese quails. However, since the publication of NRC (1994), new information on quail protein requirements is still lack C 2016 Poultry Science Association Inc. Received May 15, 2016. Accepted July 31, 2016. 1 Corresponding author: [email protected]

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wk of age (P < 0.05). In addition, as dietary CP decreased from 25.32 to 17.61%, feed intake and feed/gain were increased linearly (P < 0.05), whereas CP intake showed the opposite trend and decreased gradually. On the other hand, the carcass yields of quail were not influenced by reducing dietary CP at 42 day of age (P > 0.05). Based on broken-line regression, 23.0%, 22.5%, and 20.4% were the minimum dietary CP to keep weight gain similar to the quails fed with 25.32% CP diets during the third, fourth, and fifth wk of age, respectively. In summary, with crystalline amino acid supplementation based on a similar amino acid profile, it was possible to formulate the low-protein diets containing about 22.0% CP for growing meat quails without adverse effects on growth and carcass yields of meat quails.

ABSTRACT A dose-response experiment with 5 analyzed dietary crude protein (CP) levels (17.61, 19.73, 21.58, 23.24, and 25.32%) was conducted to investigate the effects of low-protein diets on growth performance and carcass yields of French meat quails from 15 to 42 d of age. All diets were formulated to contain a similar dietary energy level and amino acid profile. A total of 400 fifteen-day-old French quails were divided into 5 experimental treatments and each treatment contained 4 replicate pens of 20 birds (10♂+10♀). At 42 d of age, weight gain, feed intake, CP intake, feed/gain, and the yields of breast part with bone, leg part with bone, and liver of quails from each pen were measured. The results showed significant effects of the low-CP diets on CP intake, weight gain, feed intake, and feed/gain at different experiment periods except for the sixth

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WEN ET AL.

MATERIALS AND METHODS All procedures of present study were approved by the animal care and use committee of Feed Research Institute of Chinese Academy of Agricultural Sciences.

Birds and Housing A dose-response experiment with 5 dietary CP levels (17.5, 19.5, 21.5, 23.5, and 25.5%) was conducted with 15-day-old French meat quails. Six hundred oneday-old French meat quail chicks obtained from one commercial hatchery were raised with common starter diets until 14 days of age. On day 15, all birds were weighed individually and the birds with lowest or highest body weight were removed and finally 400 birds (200♂+200♀) were selected from remaining birds. Afterwards, these quails were randomly divided into five dietary treatments, each containing four replicate pens with 20 birds (10♂+10♀) per pen. The experimental diets were fed from 15 to 42 days of age. All quails had free access to water and feed and lighting was continuous. These birds from each pen were kept in plastic-wirefloor pens (200 by 100 by 40 cm) in an environmentally controlled duck house. The temperature was kept at 34◦ C (at floor level) from one to three d of age, at 31◦ C from four to seven d of age, at 28◦ C from eight to 14 d of age, and then it was reduced gradually to room temperature (24∼26◦ C). The humidity was 20% from

Table 1. Ingredient composition and nutrient content of the dilution and summit diets diets (% as-fed basis). Ingredients

Starter diet

Corn Soybean meal Corn starch Fish meal Soybean oil Dicalcium phosphate Limestone Premix1 Sodium chloride DL-Methionine L-lysine · HCL L-Threonine L-Isoleucine L-Arginine L-Leucine L-Valine L-Tryptophan Calculated values Metabolizable energy2 , kcal/ kg Crude protein Calcium Nonphytate phosphorus Methionine Cystine Lysine Arginine Isoleucine Leucine Threonine Tryptophan Valine

54.5 37.2 – 4.0 1.0 1.20 0.60 1.00 0.30 0.20 – – – – – – – 2840 23.5 0.96 0.47 0.59 0.38 1.33 1.55 0.92 1.92 0.99 0.31 1.07

Dilution diet 65.3 27.1 – 1.2 1.20 0.70 1.00 0.30 0.30 0.54 0.37 0.36 0.63 0.52 0.36 0.12 2850 17.50 0.82 0.34 0.58 0.32 1.42 1.75 1.00 2.00 1.08 0.34 1.15

Summit diet 40.30 50.10 3.2 3.20 1.10 0.60 1.00 0.30 0.20 – – – – – –

2850 25.50 0.82 0.34 0.58 0.42 1.42 1.75 1.00 2.00 1.08 0.34 1.15

1 Premix provided the following per kilogram of diets: Cu, 10 mg; Fe, 60 mg; Zn, 60 mg; Mn, 80 mg; Se, 0.3 mg; I, 0.2 mg; vitamin A, 10,000 IU; vitamin D3 , 3,000 IU; vitamin E, 20 IU; vitamin K3 , 2 mg; thiamin, 2 mg; pyridoxine hydrochloride, 4 mg; cobalamin, 0.06 mg; calcium-Dpantothenate, 20 mg; nicotinic acid, 50 mg; folic acid, 1 mg; riboflavin, 8 mg; biotin, 0.2 mg. 2 Values were calculated according to MEn of feedstuffs for poultry provided by NRC (1994).

one to three d of age and then gradually increased to 65%.

Experimental Diets The experimental diets with 5 formulated dietary CP levels (17.5, 19.5, 21.5, 23.5, and 25.5%) were produced by blending the dilution and summit diets according to different mixing ratio of these two diets (4:0, 3:1, 2:2, 1:3, and 0:4) (Table 1). All diets were formulated to contain similar dietary energy level and crystalline amino acids were added to the experimental diets to produce similar total amino acid profiles (Table 1). The CP levels of all diets were determined by Kjeldahl procedure according to the method recommended by Standardization Administration of China (1994). The analyzed dietary CP levels of these 5 experimental diets were 17.61, 19.73, 21.58, 23.24, and 25.32%, respectively. The amino acids of all diets were analyzed according to the method recommended by Standardization Administration of China (2000). Briefly, methionine and cystine were oxidized at 0◦ C by performic acid

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protein level and a 26% CP diet may provide adequate nutrition for the 0 to 2 week starting period, followed by a 24% CP diet for a 2 to 4 week period, and a 20% CP diet thereafter. However, the amino acids in low-protein diets used by these authors may be not balanced very well because only crystalline lysine and methionine were supplemented to the diets. In addition, the same ratio of Lys, Met, Thr, Trp, and Arginine (Arg) to dietary CP in all diets would lead to less amino acid density in low-CP diets compared with high-CP diets. Usually, the formulation of low-protein diets is based on similar total or digestible amino acid profiles and was developed successfully in broilers (Kerr and Kidd, 1999; Namroud et al., 2008; Awad et al., 2014; Ospina-Rojas et al., 2014). However, no research on the formulation of lowprotein diets based on similar total amino acid profiles can be found for quail. On the other hand, the new information on the optimal protein level for growing quail is still limited. French quail is a diversified poultry species reared for commercial meat and egg production. Compared with Japanese quail, French quail has significant meat production. Therefore, the objective of our study was to examine the effects of low-protein diets with similar total amino acid profiles on growth performance and carcass yields of growing French meat quail from 15 to 42 d of age and to determine the effects of reducing dietary protein for these birds.

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LOW PROTEIN DIETS FOR MEAT QUAILS Table 2. Analyzed concentration of nutrients of experimental diets on an as-fed basis. Items

Formulated crude protein (%) 17.50

21.50

23.50

25.50

19.73

21.58

23.24

25.32%

0.56 0.32 1.26 0.98 0.28 1.74 1.04 1.87 1.11 0.52 0.90 0.84 0.89 1.22 0.93 1.77 3.48

0.56 0.31 1.24 1.03 0.31 1.74 1.03 1.89 1.13 0.54 0.94 0.87 0.91 1.24 0.98 1.79 3.52

0.55 0.30 1.23 1.02 0.29 1.74 1.09 0.89 1.15 0.57 0.96 0.89 0.92 1.29 0.12 1.84 3.61

0.57 0.32 1.27 1.04 0.33 1.76 1.12 1.90 1.16 0.61 0.98 0.95 0.98 1.31 0.14 1.89 3.74

y = l + u(r − x) Where y = weight gain or feed intake, x = dietary CP level, r = the abscissa of the breakpoint where r is taken as the requirement of dietary CP, l = the response at x = r, and u = the slope of model. In this model, y = l when x > r.

RESULTS AND DISCUSSION (formic acid:hydrogen peroxide = 9:) for 16 hours and then hydrolyzed at 110◦ C by 6 M HCL for 24 hours. The other amino acids except methionine, cystine, and tryptophan were hydrolyzed at 110◦ C by 6 M HCL for 24 hours. After that, the pH of these hydrolyzates were adjusted to 2.2 and then were analyzed by using ionexchange chromatography with an amino acid analyzer (L-800, Hitachi, Tokyo, Japan). Tryptophan was analyzed by reverse-phase high performance liquid chromatography and fluorometric detection (Waters, Inc., Milford, MA) after alkali hydrolysis at 110◦ C for 20 h with 4 M barium hydroxide. The contents of all analyzed amino acids in diets met the NRC (1994) recommendation of growing Japanese quail (Table 2). The diet from each treatment was prepared in mash form.

Measurements At 21, 28, 35, and 42 d of age, weight gain, feed intake, CP intake, and feed/gain of quails from each pen were measured, respectively. Feed intake and feed/gain were all corrected for mortality. At 42 d of age, after 12 hours feed deprivation, four quails selected randomly from each pen were euthanized by CO2 inhalation. Then breast part with bone, leg part with bone, and liver were all removed manually from carcasses and weighed and the percentages relative to live body weight at processing were also calculated. Breast and leg parts were all skinless.

Statistical Analysis Data were analyzed as a completely randomized design by the GLM procedure of SAS software (SAS Institute, 2003). When dietary treatment was significant (P < 0.05), means were compared using Duncan’s

Under the lack of protein feed resources, the studies about low-protein diets in poultry have been a hot topic for research (Bregendahl et al., 2002; Kamran et al., 2008; Blake and Hess, 2013; Burley et al., 2013). Undoubtedly, it is not possible to use lowprotein diets without supplementation of other crystalline amino acids except Met, Lys, and Thr to maintain the growth performance and carcass yield similar to poultry fed standard high-protein diets (Blake and Hess, 2013). More essential amino acids would become growth-limiting as dietary CP is decreased, but there is no information on which amino acids are limiting beside Met, Lys, and Thr in quail diets (Kaur et al., 2008; Blake and Hess, 2013). In broiler, the Met, Thr, Lys, Valine, Arg, and Trp were the critical limiting amino acids in a low-protein corn-soybean meal diet (Edmonds et al., 1985; Holsheimer and Janssen, 1991). Recently, Ospina-Rojas et al., (2014) successfully developed low-protein diets for starter and growing broilers with supplementation of crystalline Val, Ileu, and Arg beside Met, Lys, and Trp in diets. Furthermore, the significant interactive effects among amino acids were also observed in the study of low-protein diets in broilers (Siegert et al., 2015). Therefore, the Met, Lys, Arg, Trp, Thr, Ileu, Leu, and Val were all considered for the amino acid profile in our study and dietary levels of these amino acids were all formulated to be adequate for quail growth. In our study, reducing dietary CP levels had significant influence on weight gain, feed intake, and feed/gain of quail (P < 0.05) from 15 to 21, 15 to 28, and 15 to 35 d of age (Table 3). In the meantime, as dietary CP levels decreased gradually, the feed intake and feed/gain of quails increased linearly (P < 0.05), whereas weight gain showed the opposite trend compared to feed intake and feed/gain and decreased linearly (P < 0.05). The

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Analyzed concentration (%) Crude protein 17.61 Amino acid (%) Methionine 0.57 Cystine 0.31 Lysine 1.25 Threonine 1.01 Tryptophan 0.29 Arginine 1.75 Isoleucine 1.02 Leucine 1.86 Valine 1.13 Histidine 0.48 Phenylalanine 0.88 Glycine 0.83 Serine 0.85 Proline 1.18 Alanine 0.91 Asparaginic acid 1.72 Glutamic acid 3.08

19.50

multiple comparison procedure of SAS software (SAS Institute, 2003). Orthogonal polynomial contrasts were used to test the linear and quadratic effects of dietary CP on quail performance. The variability in the data was expressed as the standard error of the means (SEM) and a probability level of P < 0.05 was considered to be statistically significant. In the study, a broken-line regression model analysis (Robbins et al., 2006) was used to estimate the minimum CP requirements using the NLIN procedure of SAS software (SAS Institute, 2003). The model was as following:

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WEN ET AL. Table 3. Effects of low-protein diets on growth performance of growing meat quail.1 Dietary CP levels (%)2 Item

25.32

23.24

21.58

19.73

17.61

SEM

model

linear

quadratic

31.87a 38.73a 125.88b 3.26b

29.37b 38.37a 126.38b 3.30b

27.63c 37.12a,b 128.05a,b 3.45b

26.42c 35.17b,c 133.90a 3.82a

23.74d 33.32c 134.82a 4.05a

0.65 0.60 1.23 0.08

< 0.001 0.005 0.026 0.001

< 0.001 0.001 0.002 < 0.001

0.823 0.341 0.599 0.171

70.46a 80.52a,b 278.30c 3.46b

65.61b 81.90a 282.33b,c 3.45b

61.83c 79.86a,b 286.52a–c 3.59b

58.18d 76.45b,c 294.88a,b 3.86a

53.05e 74.02c 301.24a 4.07a

1.43 0.88 2.69 0.06

< 0.001 0.009 0.023 < 0.001

< 0.001 0.001 0.001 < 0.001

0.973 0.130 0.667 0.066

132.66a 120.68a 523.93c 4.34c

123.48b 119.64a 531.31b,c 4.44b,c

114.71c 120.00a 531.55b,c 4.43b,c

107.20d 118.49a 543.33a,b 4.59b

97.06e 113.33b 551.19a 4.86a

2.86 0.9 2.81 0.05

< 0.0001 0.0472 0.0034 0.0002

< 0.001 0.008 0.001 < 0.001

0.898 0.135 0.509 0.048

178.16a 136.8 703.64 5.15 1.25

163.52b 135.88 703.62 5.18 1.25

152.48c 136.85 706.56 5.17 0.00

140.14d 134.92 710.31 5.27 2.50

126.57e 134.11 718.73 5.36 3.75

4.13 0.92 2.39 0.04 –

< 0.0001 0.8825 0.2395 0.3806 –

< 0.001 0.378 0.036 0.069 –

0.528 0.775 0.377 0.489 –

Within a column, values not sharing a common superscript letter are significantly different (P < 0.05). Values are the means of 4 replicates of 20 ducks. 2 Analyzed value. a–e 1

quails at low-CP level consumed more feed (P < 0.05) and had poorer feed/gain (Table 3). Our results were not in agreement with the results observed in bobwhite quail from 2 to 6 weeks of age by Blake and Hess, 2013. In their study, reducing dietary CP from 26 to 22% did not influence the final body weight, weight gain, and feed/gain of these birds but feed intake decreased markedly when dietary CP reduced from 22 to 20%. The reason for these differences between their and our results may be that no other crystalline amino acids except Lys and Met were supplemented in their diets compared with our study. In fact, more feed consumption and poorer feed conversion efficiency could be found in other poultry research in low-CP diets compared with a high CP diet, such as Pekin ducks (Zeng et al., 2015) and broiler (Aletor et al., 2000; Bregendahl et al., 2002). In the present study, compared with other quails fed high CP diets, the quails fed low-CP diets consumed more feed but had the smaller weight gain and this phenomenon may be due to the few net CP intakes in lowCP diets (Table 3). In addition, reducing dietary CP levels had no significant influence on weight gain, feed intake, and feed/gain of quail (P < 0.05) from 15 to 42 d of age (Table 3). This indicates that the protein requirements reduced gradually with the growth of the quails and the low-CP diets could meet the growth and development requirements at later growth stages of quails. Muscle meat is one of main edible parts in meat quail, and higher yield of breast and leg muscle means higher economic value for meat quails producers. Dietary protein levels were reported to influence muscle yield in broilers (Bartov and Plavnik, 1998; Rezaei et al., 2004) and growing ducks (Zeng et al., 2015). Therefore, the effects of dietary CP levels on carcass yield were

examined in our study. As shown in Table 4, the carcass yields of quails at 42 d of age were not influenced by reducing dietary CP from 25.32 to 17.61% (P > 0.05). In male pharaoh quail, it was found that a lowered level of protein in the diet did not affect quail slaughter yield, breast part, and leg participation in body weight (Tarasewicz et al., 2007), which is in agreement with our research. Similar result also was found in the research of growing Muscovy ducks. Baeza and Leclercq (1998) reported that no significant effect in carcass yield of Muscovy ducks was observed when dietary CP was reduced from 160 g/kg to 124 g/kg in diets based on a similar amino acid profile. In male Japanese quail, dietary CP decreasing from 300 g/kg to 160 g/kg led to a decrease in carcass yield (Kirkpinar and O˘ guz, 1995). However, in their study, the amino acids in diets may be not balanced very well because no extra amino acids were supplemented to the diets. If the ratio of total amino acids in diets was not balanced and it would lead to more reduction of total amino acids in diets as dietary CP decreased, which may lead to the difference in carcass yield between their and our results. It is well known that low-protein diets are beneficial to environment protection and ammonia emission and nitrogen excretion would be reduced markedly if such diets were applied to the poultry industry, which has been confirmed in broilers (Namroud et al., 2008; Hern´ andez et al., 2012; Ospina-Rojas et al., 2014). In our study, as dietary CP decreased, the CP intake decreased linearly (P < 0.05, Table 3), which may led to the reduction of ammonia emissions and nitrogen excretion. Therefore, it was useful to predict the minimum protein requirement of quail. In the past, many regression models could be used to determine the

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15 to 21 d CP intake (g/bird) Weight gain (g/bird) Feed intake (g/bird) Feed/Gain (g/g) 15 to 28 d CP intake (g/bird) Weight gain (g/bird) Feed intake (g/bird) Feed/Gain (g/g) 15 to 35 d CP intake (g/bird) Weight gain (g/bird) Feed intake (g/bird) Feed/Gain (g/g) 15 to 42 d CP intake (g/bird) Weight gain (g/bird) Feed intake (g/bird) Feed/Gain (g/g) Mortality (%)

P-value

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LOW PROTEIN DIETS FOR MEAT QUAILS Table 4. Effects of low-protein diets on carcass yield of growing meat quail at 42 day of age.1 Breast part with bone Dietary CP levels (%)

2

25.32 23.24 21.58 19.73 17.61 Pooled SEM P-value Model Linear Quadratic 1 2

Leg part with bone

Liver

Weight (g)

Yield (%)

Weight (g)

Yield (%)

Weight (g)

Yield (%)

49.96 50.57 50.88 49.01 48.24 0.43

22.48 22.11 22.93 23.33 23.35 0.21

31.69 31.89 30.98 30.31 30.43 0.25

14.25 13.98 13.98 14.43 14.75 0.15

4.36 5.26 4.94 4.42 4.68 0.14

1.94 2.28 2.21 2.08 2.24 0.06

0.313 0.884 0.251

0.323 0.298 0.369

0.236 0.102 0.186

0.242 0.052 0.846

0.145 0.021 0.953

0.390 0.14 0.203

Values are the means of 4 replicates of 20 ducks. Analyzed value.

Feeding period 15–21 15–28 15–35

Response criteria

Broken-line model

R2

P-value

Requirements

Weight gain Weight gain Weight gain

Y = 38.55−0.9551 × (23.0 − x) Y = 81.21−1.4632 × (22.5 − x) Y = 120.1−2.4340 × (20.4 − x)

0.996 0.970 0.984

0.004 0.031 0.016

23.0 ± 0.3359 22.5 ± 0.7689 20.4 ± 0.3186

nutritional requirements of poultry, including brokenline, quadratic, and quadratic broken-line regression models and so on (Pesti et al., 2009). In fact, researchers may consider optimal regression models according to the maximum growth performance or profitability. In our study, broken-line regression was used because this regression was successfully used to estimate protein and amino acid requirements in animals (Yang et al., 2002; Mehri et al., 2015). According to broken-line regression, the estimated protein requirements for weight gain in different growing periods were 23.0% from 15 to 21 d of age, 22.5% from 15 to 28 d of age, and 20.4% from 15 to 35 d of age (Table 5). It indicated that the protein requirements reduced gradually with increasing age of quail. These estimated protein requirements were lower than the NRC (1994) recommendations for Japanese quail (24%) and bobwhite quail (26%). In conclusion, with crystalline amino acid supplementation based on a similar amino acid profile, it is possible to reduce the dietary CP level of French quail without adverse effects on growth performance and carcass yield. According to broken-line regression, 23.0% 22.5%, and 20.4% were the minimum dietary CP to keep the weight gain similar to quails fed 25.32% CP diets from 15 to 21 days of age, from 15 to 28 d of age, and from 15 to 35 d of age.

ACKNOWLEDGEMENTS This research was supported by the Agricultural Science and Technology Innovation Program (ASTIPFRI07).

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Table 5. Protein requirements on different feeding period according to broken-line regression.

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