Layer performance of four strains of Leghorn pullets subjected to various rearing programs

Daily feeding frequency affects feed intake and body weight management of growing layers

The objective of this study was to investigate the effect of feeding behavior on feed intake and body weight in growing layers and the underlying mechanisms, thereby providing a scientific foundation for optimal feeding practices in growing layers' management. A total of 144 Hy-line brown growing layers of 10 wk old and similar body weight, were divided into 3 treatment groups with different feeding frequency and equal cumulative daily feeding amount: the once-a-day feeding group (F1) was fed at 9:00 am every day, with feeding amount of 150 g/layer; the twice-a-day feeding group (F2) were fed at 9:00 am and 13:00 pm every day, with each feeding amount of 75 g/layer; the 4 times-a-day feeding group (F4) were fed at 9:00 am, 11:00 am, 13:00 pm, and 15:00 pm every day, with each feeding amount of 37.5 g/layer. Pre-experiment lasted for 1 wk and formal experiment lasted for 8 wk. The results indicated that the daily feed intake and body weight were decreased (P < 0.05) while feed conversion ratio was not affected (P > 0.05) as daily feeding times increased. The glandular stomach proportion was significantly increased in twice-a-day feeding group, while liver proportion and ileum length were significantly increased in 4 times-feeding group (P < 0.05). Additionally, 4 times-feeding daily resulted in a significant elevation of blood glucose levels, which may have suppressed feed intake (P < 0.05). In 4 times-feeding group, the plasma triglyceride levels increased as feeding times, accompanied by a notable up-regulation in the mRNA level of appetite-suppressing gene, hypothalamic pro-opiomelanocortin (POMC) and glandular stomach ghrelin. This modulation effectively suppressed the subsequent feed intake and body weight. Therefore, 4 times feeding daily is recommended in growing layers' management, because it reduced the feed cost without affecting the feed conversion efficiency.

Effect of body weight at photostimulation on productive performance and welfare aspects of commercial layers

OBJECTIVE

Due to current selection practices for increased egg production and peak persistency, the production profile, age at maturity, and body weight criteria for commercial layers are constantly changing. Body weight and age at the time of photostimulation will thus always be the factors that need to be adequately addressed among various production systems. The current study was carried out to determine the effects of pullets' body weight (low, medium, and heavy) on their performance, welfare, physiological response, and hormonal profile.

METHODS

With regard to live weight, 150 16-week-old pullets were divided into three groups using a completely randomized design (CRD) and held until the 50th week. One-way analysis of variance was used to evaluate the data under the CRD, and the least significant difference test was used to distinguish between treatment means.

RESULTS

In comparison to the medium and light birds, the heavy birds had higher body weight at maturity, an earlier age at maturity, and higher egg weight, eggshell weight, eggshell thickness, egg yolk index, breaking strength, egg surface area, egg shape index, egg volume, and hormonal profile except corticosterone. However, the medium and light birds had lower feed consumption rates per dozen eggs and per kilogram of egg mass than the heavy birds. Light birds showed greater body weight gain, egg production, and egg specific gravity than the other categories. At 20 weeks of age, physiological response, welfare aspects, and catalase were non-significant; however, at 50 weeks of age, all these factors-aside from catalase-were extremely significant.

CONCLUSION

The findings of this study indicate that layers can function at lower body weights during photostimulation; hence, dietary regimens that result in lighter pullets may be preferable. Additionally, the welfare of the birds was not compromised by the lighter weight group.

Effects of energy restriction during growing phase on the productive performance of Hyline Brown laying hens aged 6 to 72 wk

The aim of this study was to assess the effects of energy-restricted feeding during growing phase on the productive performance of Hyline Brown laying hens aged 6 to 72 wk. A total of 720 six-week-old layer chicks were allocated equally to 3 groups with 6 replicates of 40 pullets each, and were fed 1 of 3 diets that were nutritionally similar except for the apparent metabolizable energy corrected for nitrogen (AMEn) content. At the age of 6 to 17 wk, the pullets in the control group were given diet with 2,850 kcal/kg AMEn, and were fed ad libitum. The levels of AMEn in diet of pullets in the experimental groups were 90% (2,565 [2,850 × 90%] kcal/kg) and 80% (2,280 [2,850 × 80%] kcal/kg) of that in control group, and the daily amount of feed was restricted to the absolute quantity of the diet consumed by pullets in control group. At the age of 18 to 72 wk, all the hens were fed with the same diets ad libitum. As energy restriction increased in the growing phase, body weight (BW) dropped at the ages of 12 and 15 to 23 wk (at 23 wk: P = 0.001; at other ages: P < 0.001), but it showed no significant difference at 24 wk (P = 0.071). At 20 wk, restricting energy induced a delay in the development of sexual organs, including the ovary stroma, oviduct, and small yellow follicle (P < 0.05), as well as a delay in sexual maturity (P < 0.05). Consequently, the laying rate in the first and second periods dropped linearly (P = 0.046, 0.030, and 0.038, P < 0.001, respectively). The coefficient of variation (CV) in the BW at 19, 20, and 21 wk (P = 0.040, 0.023, and 0.042, respectively), the CV of age at first egg (P < 0.001), and CV of individual egg number at age 18 to 72 wk (P < 0.001) decreased linearly. There was a linear increase in the laying rate of hens in the later periods (at age 32-72 wk, P < 0.05), as well as in the average total egg number per hen and average laying rate at the age of 18 to 72 wk (P = 0.006). The average egg mass also showed a linear increase with increasing levels of energy restriction (P < 0.001). In summary, although appropriate energy restriction during growing phase delayed sexual maturity and sexual organ development in early-laying Hyline Brown pullets, it improved uniformity of BW, age at first egg laying, and individual egg number, and increased egg number per hen, laying rate, average egg mass, and number of settable eggs from 18 to 72 wk of age.

Comparative evaluation of different moulting methods on productive performance, egg quality, and antibody response of leghorn hens

The aim of the study was to compare three moulting procedures and their effect on productive performance, egg quality, and antibody response of leghorn hens. For this, a total of 324 laying hens were distributed into three treatment groups having 12 replicates of 9 birds each according to completely randomized design. Treatments consisted of three moulting procedures based on feed and light restriction. The targeted weight at the end of moulting was 1450-1470 g. As soon as the moulting procedure is complete, the comparative analysis of post-moult productive performance (feed intake, egg production, egg weight, egg mass, feed per dozen eggs, feed per kg egg mass, livability), egg quality characteristics (egg weight, egg length and width, shape index, surface area, volume, albumen height, weight, Haugh unit score, yolk width, height, index, egg shell pore number, shell weight, thickness, breaking strength), and antibody response against Newcastle disease and avian influenza (H-9) were evaluated. Birds subjected to moulting procedure 3 (8 days fasting and gradual decrease in light) showed improvement in productive performance, egg geometry and quality traits, and antibody response against Newcastle disease virus. Birds experienced moulting procedure 1 (11 days fasting) had improved feed intake, egg production, and livability. However, birds moulted with procedure 2 (6 days fasting) revealed intermediate result in all the studied parameters. In conclusion, moulting through feed and light restriction with 8 days fasting and gradual reduction in light has potential to improve performance of leghorn hens.

Water scarcity can be a critical limitation for the poultry industry

Water is essential for various physiological functions and the productive performance of animals. However, with climatic uncertainties exacerbated by climatic changes, water could become a scarce nutrient shortly. This is already the case in one-third of the world's countries, which are under medium to high levels of water stress. Accordingly, with the growth of poultry production, the availability of water at ad libitum level may not be guaranteed, and birds can be under water restriction for variable periods. Thus, this article aims at attracting the attention of animal scientists to the freshwater shortage challenge, as well as shedding light on (1) the effects of climate change on the freshwater resources; (2) the effects of limited access to water, either by water restriction (WR) or water deprivation (WD), on the growth, feed efficiency, and meat quality of broilers; (3) the effects of different levels of WR or WD on egg production and egg quality traits; (4) the effects of limited access to water on the health, behavior, and welfare status of chickens; and (5) suggested solutions to overcome future water shortage challenges. In conclusion, severe water shortage/restriction might negatively influence the productivity, behavior, and welfare status of the chickens. Genetic background and environmental conditions may interact with the WR effects. The tolerance level of indigenous chicken breeds to limited water access could provide the knowhow to potential solutions to overcome water shortage problems. Selection of chicken strains with high tolerance capacity to thirst and limited water access regimens may be a sustainable solution for solving water scarcity problems.

Association of feed efficiency with organ characteristics and fatty liver haemorrhagic syndrome in laying hens

Poor feed efficiency (FE) in hens impacts body weight (BW) and may reflect suboptimal health. Fatty Liver Haemorrhagic Syndrome (FLHS) is mostly observed in laying hens and affects egg production and hen performance. The aim of this study was to investigate the relationships of FE and BW with organ characteristics, liver composition and incidence of FLHS of 150 individually housed ISA Brown hens ranked on the basis of feed conversion ratio (FCR) attained from early lay. At 45 weeks, 10 birds per FE group (HFE-High feed efficient; MFE-medium feed efficient; LFE-low feed efficient) were randomly selected and euthanized. Hen BW was positively associated with feed intake and FCR. The HFE hens had a lower abdominal fat pad and liver weight compared to LFE hens. FLHS lesion score was higher (worse) in the LFE than HFE hen group and was moderately positively associated with BW and abdominal fat pad, but strongly positively associated with liver weight. Liver pathology of LFE hens showed hepatocytes with abnormal retention of lipids causing distended cytoplasmic vacuoles compared to the HFE hens. Hens which exhibited poorer FE in early lay had heavier abdominal fat pads, heavier, fatter livers and were more prone to FLHS.

Laying hens under smallholder conditions: laying performance, growth and bone quality of tibia and femur including essential elements

The study aimed to assess laying performance, growth rate, and bone quality properties of tibia and femur bones of various genotypes of laying hens, including determining essential element composition at the end of the laying cycle in smallholder conditions. The study included three genotypes of laying hens; Czech golden spotted (CGS), White Leghorn (LE) and Dominant Partridge D300 (D300) hens. In total, 180 hens (60/genotype) were used in 3 replications (20 hens/replication). The eggs were collected to determine egg lay and hen-day egg production. Additionally, feed consumption was recorded to determine feed consumption per day or egg, resp. The mortality rate was recorded. Hens were individually weighed every 10 wk to analyze the growth performance and body weight changes during the laying cycle. The differences in performance characteristics were observed as significant in all studied parameters. The bone quality analysis consisted of the determination of bone weight, length, width, and fracture toughness. Furthermore, dry matter, ash, and selected elements, which included boron (B), calcium (Ca), cadmium (Cd), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), sodium (Na), phosphorus (P), lead (Pb), and zinc (Zn) were assessed. Regarding the results of tibia and femur bones, the effect of genotype was determined as significant in all evaluated properties. In terms of element composition, all evaluated elements significantly differed among the genotypes in the tibia (with one exception of Cu) and in the femur (with one exception of Cd). In conclusion, our results showed that hens’ performance, production quality, mortality and bone properties significantly differed among genotypes under smallholder conditions. Thus, every genotype needs to be carefully considered, when the rearing conditions are set.

An evaluation of bird weight and diet nutrient density during early lay on ISA brown performance, egg quality, bone characteristics and liver health

This study compared the impact of a higher nutrient density (HND) or lower nutrient density (LND) diet fed during early lay to either heavier weight (HW) or lighter weight (LW) ISA Brown hens. At 18 wk of age (WOA) pullets (n = 240) were evenly assigned to either HW (n = 120) or LW (n = 120). Sixty birds from each weight group were then randomized to either the HND or LND diet treatments which were fed from 18 to 24 WOA inclusive. At 25 WOA the LND diet replaced the HND diet. All hens remained on LND diet to 50 WOA. Hen performance was measured from 18 to 50 WOA. Femur and liver health were evaluated at 50 WOA. Egg quality was assessed from 46 to 50 WOA. The 18 WOA HW hens had higher BW, cumulative egg production, cumulative feed intake (CFI), and cumulative egg mass (CEM) to both 24 and 50 WOA (P < 0.01). At 24 WOA the HND diet also generated higher BW (P < 0.001), CEM (P < 0.001) and lower cumulative feed conversion ratio (CFCR) (P < 0.01), the latter being sustained to 50 WOA (P < 0.01). At 50 WOA CFCR of LW birds was lower than HW birds (P < 0.01). Egg weight (EW), yolk diameter, and percent yolk weight were higher (P < 0.05) in the HW birds with the highest albumen to yolk ratio in LW birds (P < 0.05). Egg shape index was higher in LND diet fed birds (P < 0.01) while LW hens had higher shell phosphorus (P < 0.05). Body weight and diet nutrient density interacted on femoral diameter and cortical thickness being higher (P < 0.01) in LW birds fed HND than LW birds fed LND diets. Fatty liver hemorrhagic scores (P < 0.05) and liver lipid peroxidase (P < 0.001) at 50 WOA were higher in HW and LND diet treatments. Concurrently HW birds had the highest CFI and EW while CFCR and liver health were superior in LW and the HND diet treatment.

The Effect of Feeding Restriction on the Microbiota and Metabolome Response in Late-Phase Laying Hens

Simple Summary

Feeding restriction (FR) is essential to reduce excessive fat deposits caused by overfeeding in hens and to ensure their reasonable nutritional requirements for egg production. Effective FR is particularly crucial for raising hens in the late phase of laying; because hens require lower energy at this stage, overfeeding reduces their feed efficiency and increase feed costs. The gut microbiota is involved in various metabolic pathways of laying hens, including in late-phase age. Thus, changes in feeding interventions can alter the presence of gut microorganisms and the structure of the microbial community, resulting in altered metabolic regulation. In this study, we investigate the microbiota and metabolome responses of late-phase laying hens under FR. Our results provide data to access the profile of the cecal bacteria community, their relevance to cecal and serum metabolites, and their FR biosynthetic pathways related to host nutritional requirements and intestinal nutrient availability. Moreover, understanding the principles of host-microbial interaction is essential for developing cost-effective strategies to improve laying hens’ production.

Abstract

This study investigated cecal bacterial community profile, cecal and serum metabolites, and its biosynthesis pathway in late-phase laying hens during 6 weeks feeding restriction (FR), using 16S rDNA as gene sequencing and non-targeted LC-MS/MS as metabolomics approach. We used three groups (ad libitum, FR20, and FR40). FR can reduce excessive fat in late-phase laying hens, while egg production rate is not affected, except for the FR40 group. In phylum level, FR20 had more population of Bacteriodetes and Firmicutes amongst groups. The same result is at genus level, FR20 were higher of the predominant genus (Bacteroides and Rikenellaceae_RC9_gut_group). Both of FR20 and FR40 reduced Proteobacteria as potential pathogenic bacteria. Non-targeted metabolomic analysis revealed that FR20 modified 20 metabolites in cecal and 10 metabolites in serum of laying hens, whereas 48 cecal metabolites and 31 serum metabolites has revealed in FR40. KEGG assay showed FR20 and FR40 upregulated lipid, carbohydrate, amino acid, nucleic acid pathway, and FR40 modified steroid metabolism in cecal analysis. In serum, only FR40 modified lipid, amino acid pathway, and carbohydrate biosynthesis were shown. This study showed that FR during late-phase laying hens altered the microbiome composition, modified metabolites profile and biosynthesis of the cecal as well as serum.

Effects of Energy-Restricted Feeding during Rearing on the Performance, Uniformity, and Development of Rugao Layer Breeders at the Initiation of the Laying Period

Simple Summary

Three major factors affecting productive performance of laying hens are BW, flock uniformity, and GIT development at the initiation of the laying period. Various feeding management practices to restrict feed intake of broiler breeders during the rearing phase to optimize BW for reproductive performance can improve BW uniformity. Hence, the feed restriction methods used for broiler breeders might be used to improve flock uniformity and the GIT development of laying hens. The objective of the study was to investigate the effects of energy-restricted feeding and switching to ad libitum feeding on the performance, uniformity, and development of Rugao layer breeders at the initiation of the laying period. Moderate energy restriction from 8 to 18 weeks of age and switching to ad libitum feeding can stimulate the development of the GIT and improve BW uniformity of layer breeders. Improved ECR was observed overall in the experiment. In addition, the BW of layer breeders recovered after the pullets were switched to ad libitum feeding for 3 weeks. These results provide a theoretical basis for the application of energy-restricted feeding in young layer breeders, which may have important practical importance for layer breeders because a better rearing cycle can be advantageous to production performance.

Abstract

The aim of this study was to assess the effects of energy-restricted feeding during rearing on the performance, uniformity, and development of layer breeders at the initiation of the laying period. A total of 2400 8-week-old Rugao layer breeders were randomly assigned to one of five groups (480 pullets per group) with eight replicates and were fed one of five diets that were nutritionally equal with the exception of apparent metabolizable energy corrected for nitrogen (AME_n) content (2850, 2750, 2650, 2550, and 2450 kcal AME_n/kg) from 8 to 18 weeks of age. The daily amount of feed was restricted to the absolute quantity of the diet consumed by laying hens fed 2850 kcal AME_n per kg diet ad libitum (control). From 18 to 21 weeks of age, all hens were fed a basal diet ad libitum. The body weight (BW) of the laying pullets decreased linearly with increasing energy restriction (p < 0.001) but recovered within 3 weeks of ad libitum feeding (p = 0.290). A gradual increase in the degree of energy restriction resulted in a gradual decrease in average daily weight gain (ADG) and a gradual increase in the feed conversion ratio (FCR) and energy conversion ratio (ECR) from 8 to 18 weeks of age (p < 0.001, p < 0.001, p = 0.008). In contrast, the ADG and ADFI (p < 0.001, p < 0.001) gradually increased, while the FCR and ECR (p < 0.001, p < 0.001) gradually improved from 18 to 21 weeks of age. From 8 to 21 weeks of age, ECR improved (p = 0.005) with an increasing degree of energy restriction. The energy-restricted feeding for 6 weeks to the end of the trial improved BW uniformity (p < 0.05). The relative length and circumference of tarsus (p < 0.001, p < 0.001), and the relative weights and lengths of the small intestine, duodenum, jejunum, ileum, and caeca increased linearly (p < 0.001, p = 0.012, p < 0.007, p = 0.012, p = 0.040; p < 0.001, p = 0.003, p = 0.032, p = 0.029, p = 0.040) with increasing energy restriction at 18 weeks of age. After switching to ad libitum feeding for 3 weeks, the relative weights and lengths of the small intestine, duodenum, and jejunum of laying pullets increased linearly with increasing energy restriction (p < 0.001, p = 0.016, p = 0.011; p = 0.009, p = 0.028, p = 0.032). In conclusion, moderate energy restriction (85.97%, 2450 vs. 2850 kcal AME_n/kg) from 8 to 18 weeks of age and switching to ad libitum feeding from 18 to 21 weeks of age can be used to improve BW uniformity and stimulate the development of the duodenum and jejunum of native layer breeders at the initiation of the laying period without compromising BW.

Effects of energy-restricted feeding during rearing on sexual maturation and reproductive performance of Rugao layer breeders

The aim of this study was to assess the effects of energy-restricted feeding during rearing on the sexual maturation and reproductive performance of Rugao layer breeders. A total of 2,400 8-wk-old Rugao layer breeders were randomly assigned to one of 5 groups (480 pullets per group) with eight replicates and were fed one of 5 diets that were nutritionally similar with the exception of apparent metabolizable energy corrected for nitrogen (AME_n) content (2,850, 2,750, 2,650, 2,550, and 2,450 kcal AME_n/kg) from 8 to 18 wks of age. The daily amount of feed was restricted to the absolute quantity of the diet consumed by laying hens fed 2,850 kcal AME_n per kg diet ad libitum (control). From 18 to 52 wks of age, all hens were fed basal diets ad libitum. The body weight of layer breeders at 18 wks of age decreased linearly with increasing energy restriction (P < 0.001), but caught up within 3 wks of ad libitum feeding (P = 0.290). The coefficient of variation of the body weight of the hens at 18, 21, and 24 wks of age decreased linearly (P = 0.010, 0.025, and 0.041, respectively) with increasing energy restriction during rearing. Energy-restricted feeding delayed sexual organ development at 18, 20, and 22 wks of age, including the number of large yellow follicles, oviduct length, oviduct length index, oviduct index, and ovary stroma index (P < 0.05), and delayed sexual maturity, including the age at laying the first egg and the age at 5% and 50% egg production (P = 0.042, 0.004, and 0.029, respectively). Consequently, egg number from 5% to 50% egg production decreased linearly as the degree of energy restriction increased (P = 0.001) and egg production of hens in the energy-restricted feeding groups was lower than that of hens in the ad libitum feeding group (6.36, 6.43, 6.4, and 4.61% vs. 14.29%; P < 0.05) from 18 to 20 wks of age. Furthermore, egg weight increased linearly as energy restriction increased (P < 0.001) and laying hens in the most severe energy-restricted feeding group had more setting eggs (normal eggs weighing >40 g) than hens in the ad libitum feeding and lighter energy-restricted feeding groups (149.57 vs. 144.34, 142.66, 143.63, and 141.78; P < 0.05). No significant differences were observed in fertility, hatchability of fertile eggs, and hatchability of setting eggs (P = 0.381, 0.790, and 0.605, respectively). In conclusion, moderate energy restriction (85.97%, 2,450 vs. 2,850 kcal AME_n/kg) from 8 to 18 wks of age increased egg weight as well as the production of setting eggs in native layer breeders throughout the laying period, without adverse effects on productive performance from 18 to 52 wks of age, or fertility and hatchability at 52 wks of age.

Effect of high concentrations of dietary vitamin D3 on pullet and laying hen performance, skeleton health, eggshell quality, and yolk vitamin D3 content when fed to W36 laying hens from day of hatch until 68 wk of age

The objective of this experiment was to investigate the effects of various dietary concentrations of vitamin D₃ (D₃) on pullet and laying hen performance, eggshell quality, bone health, and yolk D₃ content from day of hatch until 68 wk of age. Initially, 440 Hy-line W36-day-old chicks were randomly assigned to 5 dietary treatments: 1,681 (control); 8,348; 18,348; 35,014; 68,348 IU D₃/kg. At 17 wk of age, pullets were assigned to experimental diets with 12 replicate groups of 6 birds. At 17 wk of age, pullets fed diets containing 8,348 and 35,014 IU D₃/kg had an increased bone mineral density in comparison to the control fed birds (P ≤ 0.01). Body weights of pullets fed the diet with 68,348 IU D₃/kg were lower than other treatments (P ≤ 0.01). Hen-housed egg production (HHEP) of hens fed the 35,014 IU D₃/kg diet was increased in comparison to control-fed hens (P ≤ 0.01), whereas HHEP of those fed 68,348 IU D₃/kg diet was reduced in comparison to all other treatments (P ≤ 0.01). Shell breaking strength of eggs from hens fed 8,348, 35,014 and 68,348 IU D₃/kg was increased in comparison to eggs from control-fed birds (P ≤ 0.01). Fat-free tibia ash content of hens fed any of the diets supplemented with D₃ (8,348 to 68,348 IU D₃/kg) was increased in comparison to control-fed hens (P ≤ 0.05). Yolk D₃ content increased linearly with dietary D₃ and the D₃ transfer efficiency for the control, 8,348 IU, 18,348 IU, 35,014 IU, and 68,348 IU D₃ treatments were 8.24, 10.29, 11.27, 12.42, and 12.06%, respectively. These data suggest that supplementation of dietary D₃ up to 35,014 IU D₃/kg feed maintained if not increased laying hen performance and enhanced pullet and laying hen skeletal quality as well as yolk D₃ content and eggshell quality. Feeding pullets at a higher level 68,348 IU of D₃ resulted in reduced growth and ultimately decreased performance of laying hens.

Determination of body width in brown and white layer pullets by image analyses

1. Specific legal requirements for keeping pullets are not available in the European Union. However, two of the most important rearing factors for pullets are sufficient perching and feeder space. Both factors represent horizontal space dimensions which derive from the body width of the birds. 2. The body width of two strains of layer pullets (brown (BL) and white (WL) layer pullets) based on the measurement of distances in digital images was conducted on front-view digital photographs of BL and WL pullets taken at 8, 12 and 19 weeks of life. 3. Depending on live weight, age and body position, BL pullets measured an average body width between 10.70 ± 1.10 and 13.96 ± 1.11 cm. The width of WL pullets ranged from 10.30 ± 0.86 to 13.00 ± 1.14 cm. 4. Compared with WL, BL pullets occupied more horizontal space during rearing. Age influenced the body width of BL and WL pullets at the end of rearing. The tested body positions of the pullets did not affect the measured body width. 5. The biometric data obtained in this study are a useful basis for developing legal requirements for pullets, especially for defining minimum perch width and feeder space allowances.

Influence of the main cereal and feed form of the rearing phase diets on performance, digestive tract, and body traits of brown-egg laying pullets from hatch to 17 weeks of age

The effects of the main cereal and feed form of the rearing phase diets on growth performance, gastrointestinal tract characteristics, and body traits were studied in brown-egg pullets from hatch to 17 wk of age. Eight dietary treatments that were a combination of 2 main cereals (corn vs. wheat) and 4 feeding programs were used. The feeding program consisted in feeding crumbles from 0 to 5, 0 to 10, or 0 to 17 wk of age followed by mash until 17 wk, or feeding mash continuously from 0 to 17 wk. Each treatment was replicated 9 times. From hatch to 17 wk of age, pullets fed corn had similar ADG but poorer feed conversion ratio (FCR; P < 0.001) than pullets fed wheat. Also, pullets fed crumbles continuously (0 to 17 wk) had greater ADG (12.3 vs. 11.5 g; P < 0.001) and better FCR (4.21 vs. 4.36; P < 0.001) than pullets feed mash continuously, with pullets that were changed at any age of the rearing period from crumbles to mash feeding showing intermediate results. At 17 wk of age, the relative weights (% BW) of the gastrointestinal tract and gizzard were greater in pullets fed corn than in pullets fed wheat (P < 0.01) but the relative length (cm/kg full BW) of the small intestine, body, and tarsus was not affected. Pullets fed crumbles continuously had lighter gizzards (P < 0.001), higher gizzard pH (P < 0.001), and were shorter (P < 0.01) than pullets fed mash continuously, with pullets fed the other 2 treatments being intermediate. In summary, wheat can be used in substitution of corn in pullet diets without any adverse effect on growth performance. Feeding crumbles improves pullet performance but hinders gizzard and gastrointestinal tract development. Growth performance, gastrointestinal tract, and body traits of the pullets re-adapt quickly to changes in feed form of the rearing diets.

An Introduction to the Avian Gut Microbiota and the Effects of Yeast-Based Prebiotic-Type Compounds as Potential Feed Additives

The poultry industry has been searching for a replacement for antibiotic growth promoters in poultry feed as public concerns over the use of antibiotics and the appearance of antibiotic resistance has become more intense. An ideal replacement would be feed amendments that could eliminate pathogens and disease while retaining economic value via improvements on body weight and feed conversion ratios. Establishing a healthy gut microbiota can have a positive impact on growth and development of both body weight and the immune system of poultry while reducing pathogen invasion and disease. The addition of prebiotics to poultry feed represents one such recognized way to establish a healthy gut microbiota. Prebiotics are feed additives, mainly in the form of specific types of carbohydrates that are indigestible to the host while serving as substrates to select beneficial bacteria and altering the gut microbiota. Beneficial bacteria in the ceca easily ferment commonly studied prebiotics, producing short-chain fatty acids, while pathogenic bacteria and the host are unable to digest their molecular bonds. Prebiotic-like substances are less commonly studied, but show promise in their effects on the prevention of pathogen colonization, improvements on the immune system, and host growth. Inclusion of yeast and yeast derivatives as probiotic and prebiotic-like substances, respectively, in animal feed has demonstrated positive associations with growth performance and modification of gut morphology. This review will aim to link together how such prebiotics and prebiotic-like substances function to influence the native and beneficial microorganisms that result in a diverse and well-developed gut microbiota.

The effect of calcium source and particle size on the production performance and bone quality of laying hens

The efficacy of 3 local limestone sources as potential Ca sources for laying hens was studied. Limestone sources were assessed for in vitro solubility. Four Ca sources (control, A, B, or C) and 2 particle size combinations (ground, 100% ground; or mixed, 67% ground+33% large particle) was used. The control consisted of a commercial ground limestone for the ground Ca source and oyster shell of the large particle Ca source. DeKalb laying hens were randomly placed in 32 battery cage units (n=12/cage). At 19 wk of age, hens received 1 of 8 Ca source and particle size treatments (4 replicates/treatment) until 74 wk. Egg production, feed consumption, BW, and egg quality were measured throughout. Bone mineral density (by quantitative computed tomography), breaking strength, ash, and Ca were assessed at the end of lay. In vitro solubility was dependent upon Ca source and particle size (P<0.0001) with oyster shell generally having a greater in vitro solubility than test limestone sources A, B, and C of similar particle sizes. Feed consumption (100 to 117 g/bird per day), BW (1,500 to 1,800 g), egg production (92% peak egg production), egg weight (55 to 67 g), and egg specific gravity (1.090 to 1.078) did not differ among hens fed the different Ca sources (P>0.05). Tibia bone mineral density indicated the oyster shell treatment had a lower trabecular density than Ca source A; however, all other Ca sources had similar bone mineral density for all measures (P>0.05). Hens fed the mixed Ca particle treatments consistently had greater feed consumption from 27 to 70 wk than those fed the 100% ground Ca source (P<0.05). Bone mineralization was enhanced in hens that received the mixed Ca particle treatments (P<0.05). Overall, the results of this study indicate that the local limestone sources A, B, and C would be suitable alternatives to current commercial sources of Ca for laying hens. In addition, large particle Ca did improve bone quality.

Effect of varying metabolizable energy and crude protein concentrations in diets of Pearl Gray guinea fowl pullets. 2. Egg production performance

The effect of ME and CP concentrations during the growth phase of Pearl Gray guinea fowl pullets on their egg production performance was evaluated. In a 3 x 3 factorial arrangement, five hundred forty 1-d-old Pearl Gray guinea keets were randomly assigned to experimental diets with 2,900, 3,000, and 3,100 kcal of ME/kg of diet; each contained 20, 22, and 24% CP, respectively, from 0 to 8 wk of age (WOA). From 9 to 16 WOA, experimental diets had 3,000, 3,100, and 3,200 kcal of ME/kg of diet, and each contained 17, 19, and 21% CP, respectively. At 17 to 22, 23 to 27, and 28 to 56 WOA, experimental diets were composed of 3,000, 2,900, and 2,800 kcal of ME/kg, and each had 18, 17, and 16% CP, respectively. Dietary treatments were replicated 4 times, and feed and water were provided ad libitum. Body weights were measured weekly from 0 to 22 WOA, and at 28 to 56 WOA the birds were observed for feed consumption, age at first egg, hen-day egg production (HDEP), egg weight, egg mass (EM), feed conversion ratio (FCR), internal egg quality (IEQ), shell thickness (ST), and BW at the end of each 28-d lay period for 7 consecutive periods. Mortality was recorded as it occurred. Overall, BW gains were higher (P < 0.05) in birds fed 3,000 and 3,100 Kcal of ME/kg and 24% CP from 0 to 8 WOA than other dietary treatments. Percentages HDEP, EM, and IEQ were higher (P < 0.05) and FCR was lower (P < 0.05) in pullets fed 3,000 and 3,100 kcal of ME/kg diet at 0 to 8 WOA than those fed 2,900 kcal of ME/kg. Birds on 22 and 24% CP diets at 0 to 8 WOA also exhibited higher HDEP, EM, and lower FCR than those on 20% CP diets. Thus, feeding 3,000 to 3,100 kcal of ME/kg of diet and 22 to 24% CP at 0 to 8 WOA and 3,100 to 3,200 kcal of ME/kg of diet and 19 to 21% CP at 9 to 16 WOA improved HDEP, EM, IEQ, and FCR of Pearl Gray guinea fowl laying pullets at 28 to 56 WOA.

Performance of laying pullets fed on cereal-free diets based on maize offal, cassava peel and reject cashew nut meal

1. A 70-d experiment was conducted to determine the response of 26-week-old laying pullets to cereal-free diets based on maize offal, cassava peel and full-fat cashew nut meal (CNM) in comparison with a standard 550 g maize/kg reference diet. The 4 test diets all contained 315 g CNM/kg 232.5, 155.0, 77.5 and 0.0 g/kg of maize offal in combination with 77.5, 155.0, 232.5 and 315.0 g/kg of cassava peel, respectively. 2. Pullets fed on the 4 CNM-based diets consumed (P<0.05) less food than those fed on the reference diet; they also had lower (P<0.05) rates of lay, produced less (P<0.05) egg mass, had lower (P<0.05) food conversion efficiencies and their eggs had a lighter (P<0.05) yolk colour. Pullets fed some of the CNM-based diets also gained more (P<0.05) weight, the heaviest (P<0.05) being birds reared on the diet containing 315 g/kg cassava peel. Egg weight, shell thickness and albumen height from all eggs were similar. Pullets fed on the CNM-based diets had inferior (P<0.05) retention of dry matter and protein. 4. It was concluded that feeding full-fat CNM allowed for high dietary inclusion rates of cassava peel and maize offal and the resultant diets, which contained no maize, supported satisfactory performance of laying hens.