Lack of interactions between dietary lysine or strain cross and photoschedule for male broiler performance and carcass yield

Response of meat chickens to different sources of arginine in low-protein diets

Arginine activity in broiler diets can be supplied by L-arginine (Arg), guanidinoacetic acid (GAA) and L-citrulline (Cit), all of which are commercially available. This study was conducted to assess the effects of Arg source and level on broiler performance, nutrient digestibility and carcass parameters. Day-old Ross 308 cockerels (n = 768) were assigned to one of eight dietary treatments using a completely randomized design: normal protein (NP), low protein deficient in Arg (LP) and LP with two levels of either Arg (0.238% and 0.476%), GAA (0.309% and 0.618%) or Cit (0.238 and 0.476%). The LP was 5 percentage points lower in protein level than the NP. Wheat, sorghum, soya bean meal, canola meal, and meat and bone meal-based diets were fed over three feeding phases to 6 replicate floor pens with 16 birds each. Compared to NP, birds fed LP had reduced feed intake (FI, p < 0.001), reduced body weight gain (BWG, p < 0.001) and increased feed conversion ratio (FCR, p < 0.001) from day 0 to day 35. Additions of Arg or Cit to the LP at both levels resulted in increased BWG and reduced FCR (p < 0.05). Birds fed LP with GAA added had lower FCR (p < 0.05) but not higher BWG (p > 0.05) compared with the LP observed from day 0 to day 35. Supplementation of Arg, Cit and the low level of GAA to LP resulted in increased carcass yield, bone length, diameter and ash (p < 0.05) but did not increase ileal energy or nitrogen digestibility (p > 0.05). The findings indicate that Cit is an efficacious source of Arg activity in Arg-deficient diets.

Lighting programs for male and female meat quails (Coturnix coturnix) raised in equatorial region

The aim of the present study was to evaluate the effect of lighting programs for male and female meat quails raised in an equatorial region on performance and carcass traits. A total of 1,500 sexed quails (Coturnix coturnix) was distributed in a completely randomized design in a 2 × 3 factorial arrangement, with 2 sexes (male and female) and 3 lighting programs (natural, intermittent, and continuous) with 5 replicates of 50 birds. The lighting programs were applied in the period from 7 to 49 d of age, being natural (12 h and 30 min of natural light and 11 h and 30 min of dark), intermittent (12 h and 30 min of natural light and 5 h and 30 min of artificial light, alternating lighting periods with one h and 06 min and periods of darkness with one h and 12 min), and continuous (23 h of natural + artificial light and one h of dark). Regardless of lighting program, female quails were heavier than males, and birds subjected to natural light weighed less than those exposed to continuous and intermittent lighting programs. Quails exposed to intermittent and continuous light presented higher weight gain and feed intake, and worse feed conversion ratio compared to birds under a natural light regimen. It is concluded that in an equatorial region, it is possible to use a lighting program with only natural light for raising male and female meat quails from 7 to 49 d of age.

Nutritional evaluation and utilisation of quality protein maize, Nityashree hybrid maize, and normal maize in broiler chickens

Three experiments were conducted to determine the apparent metabolisable energy, apparent digestible amino acid values, and utilisation of three maize varities in chickens: quality protein maize (QPM), hybrid maize Nityashree (HMN) and normal maize (NM). There was no significant difference in the apparent metabolisable energy (AME) content amongst the three varieties of maize. Lysine and threonine digestibilities were significantly higher in QPM compared to either HMN or NM. No difference in the digestibilities of other amino acids occurred among the three different maize varieties. There was no difference between diets containing NM or HMN for body weight gain (21 and 40 d of age) and overall feed conversion ratio (0-40 d), but values were significantly higher for QPM (and Lys-supplemented NM) diets. The relative weights of dressed meat yield and giblets were unaffected by dietary replacement of NM with QPM, HMN, or Lys supplementation of the NM diet. However, abdominal fat content decreased and breast meat yield increased with both dietary replacement of NM with QPM and Lys supplementation of the NM diet. The concentration of protein in serum was significantly increased by dietary replacement of NM with QPM. Adding Lys to the NM based diet significantly increased the Ca concentration in serum compared with NM or HMN diets. However, the highest concentration of Ca in serum was found in the QPM diet. The concentration of total cholesterol in serum significantly decreased by either replacing NM with QPM or adding Lys to the NM based diet, compared with the NM diet. These results suggested that the feeding value of quality protein maize was superior to normal maize, while the feeding value of hybrid maize Nityashree was similar to that of normal maize.

Effect of light intensity on live performance and processing characteristics of broilers

This study investigated the effects of different light intensities provided via an increasing photoperiod program on broiler live performance and processing characteristics. A total of 1,080 male broilers were evenly distributed in 12 rooms. Six rooms were subjected to intensities of either 15 footcandles (FC) from 1 to 51 d (Bright), or 0.5 FC from 1 to 9 d and 0.1 FC from 9 to 51 d (Dim). Both intensity treatments were provided in an increasing photoperiod program (23L:1D, 1 to 9 d; 12L:12D, 9 to 16 d; 14L:10D, 16 to 23 d; 17L:7D, 23 to 30 d; 20L:4D, 30 to 37 d; and 23L:1D, 37 to 51 d). Feed consumption and BW were determined, and feed conversions were calculated approximately weekly. Mortalities were necropsied and recorded daily. At 51 d, 30 birds from each room were processed and cut up to determine weights and yields. Beginning at 23 and 30 d, respectively, BW and feed consumption were greater in the Dim treatment. At 51 d, Dim treatment BW was 4.7% greater and feed consumption was 3.9% greater. Feed conversion, metabolic and total mortality, and BW uniformity were not influenced by light intensity. Weights of lean carcass, total breast, fillets, tenders, and legs were from 4.9 to 6.2% greater in the Dim treatment, which was proportional to the BW difference and resulted in similar yields of these parts. However, wings were 9.9% heavier in the Dim treatment, which resulted in greater wing yield. Equal fat pad weights resulted in reduced fat pad yield in the Dim treatment. These results indicate that BW, feed consumption, and most parts weights were increased proportionally by providing 0.1 vs. 15 FC of light intensity via an increasing photoperiod program, and that only the yields of minor parts were affected by intensity.

Efeitos dos programas de luz sobre desempenho, rendimento de carcaça e resposta imunológica em frangos de corte

Avaliaram-se os efeitos dos programas de luz 23L:1E (23L); crescente (CRES); 16L:8E (16L) e luz natural (NAT) sobre o desempenho, rendimento de carcaça e resposta imunológica de frangos de corte machos da linhagem Cobb-500. O período de criação foi de um a 45 dias de idade, e os tratamentos foram definidos de acordo com os programas de luz. O delineamento experimental foi o inteiramente ao acaso com quatro tratamentos e seis repetições de 35 aves cada. As aves submetidas ao programa de luz CRES apresentaram maior peso vivo em relação aos demais tratamentos (P<0,05). O consumo de ração também foi maior para as aves do tratamento CRES quando comparado aos tratamentos 23L e NAT (P<0,05), e semelhante ao tratamento 16L (P>0,05). A viabilidade das aves do tratamento NAT foi maior em relação às aves do tratamento 23L (P<0,05) e semelhante aos demais tratamentos (P>0,05). A conversão alimentar e o rendimento de carcaça não foram influenciados pelos tratamentos (P>0,05). As aves do tratamento 23L apresentaram maior rendimento de peito quando comparado aos demais tratamentos (P<0,05). A produção de anticorpos para a doença de Newcastle não foi afetada pelos tratamentos (P>0,05).

Effect of Light Intensity and Photoperiod on Live Performance, Heterophil-to-Lymphocyte Ratio, and Processing Yields of Broilers

This study investigated effects of light intensity and photoperiod on live and processing performance and physiological stress of broilers. One hundred broilers were housed in each of 12 rooms, provided 23L:1D with 3 footcandles (FC) of intensity to 8 d, and then subjected to the following treatments in a 2 x 2 factorial arrangement: either 1 FC (1FC) or 0.1 FC (0.1FC) from 8 to 49 d and either 23L:1D from 8 to 49 d (23L) or 18L:6D from 8 to 43 d followed by 23L:1D from 43 to 49 d (18L). At 40 d, blood samples were drawn and heterophil:lymphocyte ratios determined. At 49 d, 16 birds from each room were processed to determine weights and yields. There were interaction effects on BW from 29 to 49 d. At 29 d, BW was reduced by either 18L or 0.1FC treatments. At 43 d, BW was greatest in 1FC-23L, reduced in 1FC-18L and 0.1FC-23L, and intermediate in the 0.1FC-18L treatment. At 49 d, BW of 1FC-23L and 0.1FC-18L were similar and greater than those of 1FC-18L and 0.1FC-23L treatments. Feed consumption was reduced by 18L treatment from 15 to 29 d and the 0.1FC treatment at 15 d. Feed conversion and mortality were not affected by treatments. The 0.1FC treatment decreased uniformity at 15 d. Heterophil:lymphocyte ratios averaged about 0.45 and were not affected by treatments. Carcass yield and tender weight were reduced by the 0.1FC treatment, whereas whole breast yield was reduced by the 18L treatment. There were interaction effects on whole breast weight and fillet weight and yield, which were reduced by either the 18L or 0.1FC treatments. These results indicate that although the combination of 18L:6D and 0.1FC may result in broiler live performance comparable to that achieved with 23L:1D and 1FC, and no combination of the photoperiods and intensities tested caused physiological stress, breast meat is generally reduced by either 18L:6D or 0.1FC.

Estimation of Nitrogen Maintenance Requirements and Potential for Nitrogen Deposition in Fast-Growing Chickens Depending on Age and Sex

Experiments were conducted to estimate daily N maintenance requirements (NMR) and the genetic potential for daily N deposition (ND(max)T) in fast-growing chickens depending on age and sex. In N-balance studies, 144 male and 144 female chickens (Cobb 500) were utilized in 4 consecutive age periods (I: 10 to 25 d; II: 30 to 45 d; III: 50 to 65 d; and IV: 70 to 85 d). The experimental diets contained high-protein soybean meal and crystalline amino acids as protein sources and 6 graded levels of protein supply (N1 = 6.6%; N2 = 13.0%; N3 = 19.6%; N4 = 25.1%; N5 = 31.8%; and N6 = 37.6% CP in DM). The connection between N intake and total N excretion was fitted for NMR determination by an exponential function. The average NMR value (252 mg of N/BW(kg)0.67 per d) was applied for further calculation of ND(max)T as the threshold value of the function between N intake and daily N balance. For estimating the threshold value, the principle of the Levenberg-Marquardt algorithm within the SPSS program (Version 11.5) was applied. As a theoretical maximum for ND(max)T, 3,592, 2,723, 1,702, and 1,386 mg of N/BW(kg)0.67 per d for male and 3,452, 2,604, 1,501, and 1,286 mg of N/BW(kg)0.67 per d for female fast-growing chickens (corresponding to age periods I to IV) were obtained. The determined model parameters were the precondition for modeling of the amino acid requirement based on an exponential N-utilization model and depended on performance and dietary amino acid efficiency. This procedure will be further developed and applied in the subsequent paper.

Chicken welfare as indicated by lesions on carcases in supermarkets

1. The extent of visible lesions in British broiler carcases was investigated in order to discover the extent of any poor welfare. It is well established that hock burn and some other injuries can occur during housing of broiler chickens, whilst other injuries can occur during handling. 2. Three hundred and eighty-four whole conventionally reared British Farm Standard Grade A chickens were scrutinised in supermarkets to assess the frequency of 15 kinds of lesions. Six lesions were analysed histopathologically and this showed that hock burn would have occurred several days pre-mortem, red alular and wrist bruise were very likely to have occurred pre-mortem, whilst red parson's nose and scratches were likely to have occurred pre-mortem. 3. Many broiler carcases in the supermarkets had dermal lesions: 0.82 had hock burns, 0.45 a red parson's nose, 0.32 a red alular, 0.21 wrist bruises and 0.21 had at least one scratch on a leg. The frequency of the larger hock burns increased with body weight. 'Organic' chickens had half as many hock burns as conventionally reared broilers, perhaps because of differences in litter quality or leg strength. 4. The sample studied indicates that painful lesions which would result in poor welfare are frequent in broilers slaughtered in the UK. The Grade A chickens observed exclude birds with obvious visible defects because these birds would have had the blemishes removed and the carcase would have been portioned. Hence the frequencies of lesions in farmed birds would be higher than those reported here.

Lysine and Arginine Requirements of Broiler Chickens at Two- to Three-Week Intervals to Eight Weeks of Age

Four experiments were conducted to determine the arginine and lysine requirements of male chickens for 2- to 3-wk intervals from the time of hatching until 8 wk of age. Weight gain, breast muscle growth, and feed efficiency were used as response for each interval. Dietary requirements for lysine and arginine were estimated by broken-line regression analysis of responses to six or seven dietary levels of each amino acid. Dietary crude protein levels were 22, 21, 20, and 18% in four consecutive experiments from 0 to 2, 2 to 4, 3 to 6, and 5 to 8 wk of age. An occasional estimate of requirement was not determined (ND) because the response did not conform to the regression model. The values for lysine and arginine requirements determined from breast muscle gain (weight gain of pectoralis major plus pectoralis minor) were not significantly higher than those from body weight gain. However, they tended to be higher than for feed efficiency for 0-to-2 and 2-to-4-wk-old broilers. Lysine and arginine requirements, as percentages of total amino acid in the diet, for maximum breast muscle growth were, respectively, 1.32+/-0.01% and 1.27+/-0.00% to 2 wk of age, 1.21+/-0.06% and ND for 2 to 4 wk of age, 0.99+/-0.02% and 0.97+/-0.02% for 3 to 6 wk of age, and 0.81+/-0.01% and 0.83+/-0.02% for 5 to 8 wk of age. Calculated digestible lysine and arginine requirements were, respectively, 1.24 and 1.19% to 2 wk of age, 1.11% and ND for 2 to 4 wk of age, 0.92% and 0.91% for 3 to 6 wk of age, and 0.75 and 0.78% for 5 to 8 wk of age. The requirements for lysine and arginine were similar except for the earliest age group for which the lysine requirement appeared to be slightly higher than that of arginine.

Further studies on the influence of genotype and dietary protein on the performance of broilers

An experiment was conducted to quantify genetic differences in response to dietary protein level of male vs female broilers. Broilers (1 d old) from a "high-yield" strain cross (Ross x Ross 208) and a "fast-growing" strain cross (Peterson x Arbor Acres) were placed on fresh pine shavings in floor pens. From Day 0 to 18, all birds were fed a 23% CP starter diet. During Days 18 to 53 male birds were fed either a 16, 18, 20, 22, 24, or 26% CP diet (3,200 kcal ME/kg) and female birds were fed the 16, 20, or 24% CP diet. Significant differences (P < 0.05) were noted in the performance of the different strains. Ross x Ross 208 male birds had a higher body weight (3.37 vs 3.16 kg), higher feed intake (7.08 vs 6.78 kg), higher breast yield (31.76 vs 29.25%), higher carcass yield (73.90 vs 71.85%), and a lower adjusted feed conversion ratio (FCR; 2.10 vs 2.16 g:g) than Peterson x Arbor Acres males at 53 d of age. As compared to Peterson x Arbor Acres females, Ross x Ross 208 female broilers also had a higher body weight (2.68 vs 2.55 kg), higher breast meat yield (33.61 vs 30.80%), higher carcass yield (75.31 vs 73.91%), and lower adjusted FCR (1.97 vs 2.04 g:g). Qualitative differences in the response of these strains were confirmed and better qualitative data is presented that can be used to predict the important output parameters from the import inputs in broiler production.

Moderate excess of dietary protein increases breast meat yield of broiler chicks

Two factorial experiments were carried out to evaluate the effects of dietary protein level, expressed as energy to protein (E:P) ratio, on yields of carcass and breast and on abdominal fat pad weight of male broiler chicks at 43 and 57 d of age. Two diets similar in their energy content and differing markedly in their protein content, in which the E:P ratios were lower and identical to the NRC (1994) recommendations, were used in Experiment 1. Four diets, the combination of two energy and two protein levels, in which the E:P ratios were lower and identical to the recommendations, were used in Experiment 2. There were no differences in feed intake or weight gain until 42 d of age between broilers fed the diets with the low and those fed the recommended E:P ratio. However, feed efficiency of the former was consistently and significantly (P < 0.05) higher. The high-energy diets did not affect feed intake but significantly improved weight gain between 7 and 28 d of age and feed efficiency until 42 d of age. In both experiments, carcass yield was not affected by dietary E:P ratio at 43 d of age; however, at 57 d of age it was increased significantly by the low E:P ratio in Experiment 1 and in birds fed the high energy diet in Experiment 2. On a factorial basis, the effect of the low E:P ratio on increasing yield was significant only in Experiment 1. The high dietary energy level increased carcass yield only at 43 d of age, but on a factorial basis its effect was significant. Carcass yield was significantly (P < 0.001) higher at 57 than at 43 d of age. In both experiments, breast meat yield was negatively correlated with dietary E:P ratio, a significant factorial effect. The difference in this variable between broilers fed the diets containing the low and the recommended E:P ratio was significant, at both ages in Experiment 1, and only at 57 d of age in Experiment 2. Breast meat yield was not affected by dietary energy level, and it was significantly (P < 0.001) higher at 57 than at 43 d of age. Relative abdominal fat pad weight was increased significantly by increasing dietary E:P ratio. Dietary energy level and age did not affect this variable. The relationship between abdominal fat pad weight and breast meat yield within the treatments tended (in most of the cases not significantly) to be negative. However, this negative relationship was significant, at both ages, when the analysis was carried out with the pooled data at each age. It is concluded that the optimal E:P ratio for maximal breast meat yield for broiler chicks, particularly at 57 d of age, may be below the NRC (1994) recommendations.

Dietary interactions between lysine and threonine in broilers

Two experiments were conducted to evaluate the effects of two dietary levels of lysine and four dietary levels of threonine in a factorial arrangement on broiler growth, carcass traits, and immunity. In both experiments, 120 broilers were allocated to each of 56 floor pens (6,720 total broilers). In Experiment 1, two levels of lysine (1.10 and 1.20% of diet) and four levels of threonine (0.68, 0.74, 0.80, and 0.86% of diet) were fed to broilers from 1 to 18 d of age in a sorghum-peanut meal diet. Body weight gain, feed:gain, mortality, and cellular and humoral immunity were measured. In Experiment 2, all broilers received a common basal diet up to 18 d of age. Experimental diets were fed from 18 to 34, 34 to 44, and 44 to 54 d of age. Two levels of lysine [100 and 105% of NRC (1994) recommendations] and four levels of threonine [83, 92, 100, and 108% of NRC (1994) recommendations] were included in the experimental diets for each age group (seven replications per treatment). The diets consisted of wheat (soft), corn gluten meal, soybean meal, and meat and bone meal Weight gain, feed:gain, mortality, and carcass traits were measured at 54 d of age. In Experiment 1, increasing dietary lysine from 1.10 to 1.20% from 1 to 18 d in broilers improved (P < 0.001) BW gain (453 vs 488 g) and feed:gain (1.39 vs 1.33). No interactions between lysine and threonine were observed in Experiment 1. Differences in immune parameters or mortality were not observed. In Experiment 2, an interaction in 18 to 54 d weight gain occurred with the highest gain in broilers receiving dietary lysine and threonine levels equivalent to 100 and 83%, respectively, of NRC (1994) or lysine and threonine at levels of 105% and 100% of NRC (1994), respectively (P < or = 0.05). Supplemental lysine (105% of the 1994 NRC) improved (P < or = 0.01) 18 to 54 d feed:gain (2.30 vs 2.26). No differences in mortality occurred. Supplemental lysine increased preslaughter weight (P < or = 0.05), but differences in carcass yield were not observed. Breast fillet yields were the highest (P < or = 0.03) in broilers receiving 100% of NRC lysine and 83 or 92% of NRC threonine or 105% of NRC lysine and 100 or 108% of NRC threonine. In conclusion, additional lysine improved feed:gain independent of threonine from 1 to 54 d of age. However, lysine and threonine interact to increase weight gain and breast fillet yields.

Lighting programs for broilers that reduce leg problems without loss of performance or yield

This study tested the effects of light schedules on performance and yields of broiler chickens. In Experiment 1, light treatments during Days 1 to 49 of age were: 1) 23 h light (L):1 h dark (D); 2) 16L:8D;3) 16L: 3D:1L:4D; and 4) 16L:2D:1L:2D:1L:2D. In Experiment 2, Light Treatments 1 and 2 were the same as Treatments 1 and 4, respectively, in Experiment 1; 3) 23L:1D Days 1 to 7, 16L:8D Days 8 to 14, the light period was increased by 2 h/wk during Days 15 to 35, and 23L:1D Days 36 to 42; and 4) 23L:1D Days 1 to 7, 16L:8D Days 8 to 14, 16L:3D: 2L:3D Days 15 to 21, 16L:2D:4L:2D Days 22 to 28, 16L: 1D:6L:1D Days 29 to 35, and 23L:1D thereafter. In Experiment 1, BW was greater in Treatment 4 than Treatment 2 at 22 (708 vs 642 g) and 49 d (2,948 vs 2,797 g), percentage leg problems was lower in Treatments 2 to 4 (9, 10 and 6%, respectively) than in Treatment 1 (20%), and percentage Grade A was greater in Treatment 4 than Treatment 2 (60 vs 46%) at 49 d. In Experiment 2, BW was greater in Treatment 1 (692 g) than Treatments 3 (617 g) and 4 (620 g) at 21 d, and the incidence of tibial dyschondroplasia was lower in Treatment 2 (3.1%) than Treatment 3 (15.3%) at 42 d. There were no differences for mortality among treatments in either experiment.