Effects of Energy and Protein Levels on Laying Performance, Egg Quality, Blood Parameters, Blood Biochemistry, and Apparent Total Tract Digestibility on Laying Hens in an Aviary System

This study was performed to investigate the effects of apparent metabolizable energy (AMEn) and protein levels on laying performance, egg quality, blood parameters, blood biochemistry, and apparent total tract digestibility of energy and nutrients in diets fed to laying hens in an aviary system. A total of 560 Hy-Line Brown laying hens (age = 30 week) were distributed in a completely randomized experimental design in 2 × 2 factorial arrangements with 2 metabolizable energy levels (2700 and 2800 kcal AMEn/kg) and 2 protein levels (16.5 and 14.5% CP). Four treatments and four replicates of 40 birds each (stocking density = 15 birds/m2) were prepared. Results revealed no significant interaction between AMEn and CP in the diet in terms of egg production, floor eggs, broken and dirty egg production, egg mass, feed intake, and feed conversion ratio of laying hens. However, egg weight was affected. As dietary energy and CP levels (2800 kcal of AMEn/kg and 16.5% CP) increased, egg weight increased (p < 0.05). Egg weight, feed intake, and feed conversion ratio significantly differed (p < 0.05) as the energy content in the feed increased. Ether extract significantly varied (p < 0.05) as the energy content in the feed increased. In conclusion, laying performance and egg quality of Hy-Line Brown laying hens in the middle stage of egg production (30 to 50 weeks) were not affected by different dietary energy and protein levels, but feed intake decreased with an increasing level of AMEn in diets. Ether extract significantly varied as the energy content in the feed increased.

Influence of the energy concentration and the standardized ileal digestible lysine content of the diet on performance and egg quality of brown-egg laying hens from 18 to 41 weeks of age

The influence of the energy and the standardized ileal digestible lysine (DLys) content of the diet on egg production and egg quality, was studied in brown-egg laying hens from 18 to 41 wk of age. The experimental design was completely randomized with 10 treatments organized as a 2 × 5 factorial with 2 energy concentrations (2,750 and 2,800 kcal AMEn/kg) and 5 levels of DLys (values varied from 0.66 to 0.78% and 0.67 to 0.79%, for the low and high energy diets, respectively). Each treatment was replicated 10 times (10 hens per replicate). The data were analyzed using the MIXED procedure of SAS with energy concentration and DLys content of the diets as main effects. In addition, the effects of the DLys on the variables studied were partitioned into its lineal and quadratic components. From 18 to 21 wk of age (pre-peak phase), diet composition had limited effects on egg production. From 22 to 41 wk of age (peak phase), however, an increase of 50 kcal AMEn/kg diet increased egg weight (P < 0.05) and tended to improve energy intake (P = 0.083) and feed conversion ratio (P = 0.074). An increase in DLys improved linearly (P < 0.001) egg production, egg weight, egg mass, feed conversion, and energy conversion ratio, and tended to increase BW gain (P = 0.074). Diet composition did not any affect egg quality trait except shell strength that increased linearly (P < 0.05) with increases in the DLys. Cumulatively (18–41 wk of age), egg weight increased (P < 0.05) as the energy and the DLys content of the diet increased. In summary, an increase in energy and DLys content of the diet had limited effects on egg production during the prepeak phase but improved egg production, feed conversion ratio, and BW gain during the peak phase. The data indicate that hens require at least 839 mg DLys/d to maximize egg production in the peak production phase.

The influence of hen size and diet nutrient density in early lay on hen performance, egg quality and hen health in late lay

The effect of hen size and diet nutrient density during early lay on egg production (EP) at 24 and 69 wk of age (WOA) and late lay egg quality and hen health was evaluated. Based on bodyweight (BW) at 18 WOA ISA Brown hens were assigned as heavier (HW; n = 120) or lighter weight (LW; n =120). Sixty birds from each BW group were fed an early-lay diet of higher nutrient density (HND), or lower nutrient density (LND) between 18 and 24 WOA. From 25 WOA all hens received the same early-lay diet and then from 40 WOA the mid-lay diet. Hen average daily feed intake (ADFI), hen-day EP, egg weight (EW), egg mass (EM), and feed conversion ratio (FCR) were assessed at 24 and 69 WOA. Between 66 and 70 WOA eggshell and internal egg quality was evaluated and at 70 WOA BW, liver and bone health were assessed. At 24 WOA BW was highest in HW birds and birds receiving the HND diet (P < 0.01). Concurrently ADFI, and FCR were higher and hen-day EP was lower in HW compared to LW birds (P < 0.05). The HND diet resulted in lower ADFI and FCR at 24 WOA, but higher EW and EM compared to the LND diet (P < 0.01). At 69 WOA HW birds had higher ADFI, EW (P < 0.02) and heavier 70 WOA BW compared to LW hens. The lower FCR of the LW birds at 69 WOA was approaching significance (P = 0.054). Hen weight and diet density did not affect 69 WOA egg production. Between 18 and 69 WOA cumulative FI and EM were higher in HW hens (P < 0.01) than LW hens, as was cumulative FCR (P = 0.053). Hen weight and diet density did not alter 66–70 WOA internal egg quality, but the HND diet generated thicker eggshells and higher eggshell breaking strength (P < 0.05). Seventy WOA liver health, keel curvature and femur breaking strength did not differ. Overall LW hens had lower FCR than HW hens and the early-lay HND diet facilitated improved eggshell integrity during late lay compared to the LND diet.

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.

Effect of dietary energy density and folic acid supplementation on white striping occurrence and growth performance of broiler chickens

Broilers were allocated to eight treatments consisting of two energy levels: normal (NE) and high (HE), and four folic acid (FA) levels (2.2, 5, 10, and 15 ppm). On day 42, two male and two female chickens were euthanized per pen, and white striping (WS) evaluation was performed on the pectoralis major. Birds fed HE diets had reduced (P < 0.05) feed intake and feed conversion rate than those on NE diets. With increasing FA levels, there was reduced (P < 0.05) WS score and increased (P < 0.05) normal breast fillet percentage in female chickens but not in the males. WS scores were higher (P < 0.01) in male chickens than in the females.

Influence of the energy and digestible lysine contents of the diet on performance and egg quality traits of brown-egg laying hens from 19 to 59 weeks of age

The influence of nutrient density and standardized ileal digestible lys (DLys) content of the diet on egg production and egg quality traits, was studied in brown-egg laying hens from 19 to 59 wk of age. The experimental design was completely randomized with eight treatments arranged as a 2×4 factorial with two AMEn concentrations (2,680 and 2,780 kcal/kg) and four levels of DLys (0.68, 0.72, 0.76, and 0.80%). Each treatment was replicated nine times and the experimental unit was a cage with nine hens. Hen production, egg components (proportion of albumen, yolk, and shell), egg quality traits (Haugh units, egg shell strength, and incidence of broken, dirty, and shell-less eggs) were measured by period (28 d) and cumulatively. Data were analyzed as a completely randomized design with energy concentration, level of DLys, and their interactions as main effects. In addition, the effects of the level of DLys on the variables studied, were partitioned into its linear and quadratic components. No interactions between AMEn and DLys content of the diet were detected for any of the traits studied and therefore, only main effects are presented. An increase in the AMEn concentration of the diet from 2,680 to 2,780 kcal/kg increased energy intake (P < 0.05) and egg weight (P < 0.001) and improved feed conversion ratio (P < 0.05). An Increase in DLys from 0.68 to 0.80% did not affect the number of eggs produced but increased linearly egg weight (P < 0.01) and egg mass production (P < 0.05). Diet did not affect egg quality. In conclusion, an increase in the AMEn content of the diet from 2,680 to 2,780 kcal/kg increased egg weight and improved feed efficiency. Laying hens require no more than 744 mg DLys/d (corresponding to 0.68% DLys) to optimize egg production. However, when the objective is to maximize egg weight, hens should consume at least 843 mg DLys/d (corresponding to 0.76% D Lys).

Effects of dietary probiotic (Pediococcus acidilactici) supplementation on productive performance, egg quality, and body composition in laying hens fed diets varying in energy density

This study was conducted to determine the effect of probiotic Pediococcus acidilactici (PA) strain MA18/5M supplementation of diets with different dietary energy levels on productive performance, egg quality, and body composition in Hy-Line Brown hens during a 16-week period from 32 to 47 wk of age. The experimental treatments with a 2 × 2 factorial design received a 2 wheat–corn–soybean diet: a moderately low energy density diet with 2,650 kcal ME/kg (M-LED) and a low energy density diet based on the M-LED diet with 2,550 kcal ME/kg (LED), each diet without and with probiotic supplementation (M-LED, LED, M-LEDp, and LEDp, respectively). Reduced dietary energy levels had a particularly negative effect on egg weight (61.7 vs. 63.3 g; −2.6%, P < 0.001), egg mass output (1.67 vs. 1.71 kg; −2.4%, P = 0.015), and FCR (2.01 vs. 1.97 kg feed/kg egg; +2%, P = 0.028). In hens administered the LED diet, deteriorated productive performance was accompanied by greater body weight loss (P < 0.001) and reduced abdominal fat content (P < 0.033) as compared with the M-LED group. Dietary probiotic inclusion increased egg weight (P = 0.015), including relative eggshell weight (P = 0.008) and eggshell thickness (P = 0.002) and significantly improved FCR (P = 0.010). No interactions between the PA-based probiotic and dietary energy levels were found in any of the tested parameters. Adding the probiotic on top of the M-LED diet improved layers performance but resulted in nonbioequivalence for the egg weight, egg mass output, and FCR compared with this group without probiotic. Probiotic supplementation of the LEDp diet improved all performance parameters except for egg weight. As a result, the laying rate, egg mass output, daily feed intake, and FCR in the LEDp treatment were bioequivalent to those noted in the M-LED group without the probiotic. The results of a bioequivalence test suggest that a low energy diet fed to laying hens promoted a probiotic response to improve energy utilization by birds.

The effect of sodium stearoyl-2-lactylate (80%) and tween 20 (20%) supplementation in low-energy density diets on growth performance, nutrient digestibility, meat quality, relative organ weight, serum lipid profiles, and excreta microbiota in broilers

A total of 768 1-d-old Ross 308 male broiler chickens with an average body weight of 43.64 ± 0.59 g were used in a 5-wk feeding trial. The chickens were distributed into 4 treatments of 12 replications per treatment with 16 chickens per pen. Dietary treatments included the following: TRT1, basal diet; TRT2, -40 kcal diet + 0.05% emulsifier; TRT3, -60 kcal diet + 0.05% emulsifier; TRT4, -80 kcal diet + 0.05% emulsifier. The emulsifier contained 80% sodium stearoyl-2-lactylate and 20% tween 20. In our study, the treatment diets had no significant effect on growth performance, meat quality, relative organ weight, serum lipid profiles, and excreta microbiota. However, the birds were able to grow as well with less energy when the emulsifier was added. The supplementation of emulsifier in the low-energy diet linearly decreased cholesterol (P = 0.099) and LDL/C (P = 0.074). The fat digestion of broilers fed with TRT2, TRT3, and TRT4 was significantly higher than broilers fed with TRT1 diet. Our study result shows that the emulsifier used for the experiment is beneficial in the low-energy diet of broiler chickens.

Productive performance and blood profiles of laying hens fed Hermetia illucens larvae meal as total replacement of soybean meal from 24 to 45 weeks of age

The aim of the research was to study the effects of an insect meal from Hermetia illucens larvae (HILM) as complete replacement of soybean meal (SBM) on productive performance and blood profiles of laying hens, from 24 to 45 wk of age. A total of 108 24-week-old Lohmann Brown Classic laying hens was equally divided into 2 groups (54 hens/group, 9 replicates of 6 hens/group). From 24 to 45 wk of age, the groups were fed 2 different isoproteic and isoenergetic diets: the control group (SBM) was fed a corn-soybean meal based diet, while in the HILM group the soybean meal was completely replaced by Hermetia illucens larvae meal. Feed intake, number of eggs produced, and egg weight were recorded weekly along the trial. At 45 wk of age, blood samples were collected from 2 hens per replicate. The use of HIML led to a more favorable (P < 0.01) feed conversion ratio in hens but lay percentage, feed intake, average egg weight, and egg mass were higher (P < 0.01) in hens fed the SBM diet. Hens fed insect meal produced a higher percentage of eggs from small (S), medium (M), and extra-large (XL) classes (P < 0.01) than SBM, while the SBM group had a higher percentage of eggs from the large (L) class (P < 0.01). The levels of globulin and albumin to globulin ratio were, respectively, higher and lower (P < 0.05) in HILM than the SBM group. Cholesterol and triglycerides were higher (P < 0.05 and P < 0.01, respectively) in hens from SBM than in the HILM group. Blood levels of Ca were higher (P < 0.01) in hens fed insect meal, while creatinine was higher (P < 0.01) in blood of hens fed SBM. Hermetia illucens larvae meal can be a suitable alternative protein source for laying hens even if the complete replacement of soybean meal needs further investigation to avoid the negative effects on feed intake.

Individual and combined effects of crude protein, methionine, and probiotic levels on laying hen productive performance and nitrogen pollution in the manure

The present study aimed to investigate the effect of the dietary levels of protein, methionine (Met), as well as probiotic on productive performance, feed utilization, and environmental pollution by N in Lohmann Brown laying hens. A total number of 160 Lohmann Brown laying hens at 20 weeks of age were randomly divided into 8 treatment groups using a 2 × 2 × 2 factorial design experiment. The experiment involved two levels of crude protein (16 and 18 %), two levels of Met (0.45 and 0.50 %), and two concentrations of probiotic (0 or 1 g/kg diet, with a concentration of 10¹⁰ CFU/g of Lactobacillus acidophilus) within 20-42 weeks of age. Results revealed that egg production parameters were significantly (P < 0.01) improved for hens fed diets of 18 % CP comparing with that of 16 % protein within the period from 26 to 30 weeks of age. Protein utilization and feed efficiency values were enhanced with 0.67 and 0.72 % Met during the period of 26-30 weeks of the age. For the N pollution, results showed that increasing crude protein in the diet from 16 to 18 % caused significant (P < 0.01) increase in the excreted N from 0.349 to 0.492 g/d. The methionine level of 0.72 % recorded the highest values of total consumed N being 3.98 g/d and excreted N being 0.527 g/d comparing with the other levels. It could be concluded that the best productive performance could be given by using 0.72 % total sulfur amino acids (TSAA). Furthermore, the dietary level of 18 % CP with 0.72 % Met is preferred in feeding laying hens through the whole experimental period. Ecologically, reducing the level of crude protein in layer diets to be 16 % along with the supplementation of Met can play an important role in minimizing the pollution with N from poultry excretion.

Effects of feeding diets varying in energy and nutrient density to Hy-Line W-36 laying hens on production performance and economics

The objectives of this study were to evaluate the effects of feeding 5 different energy and nutrient dense diets to Hy-Line W-36 hens on long-term performance and economics. A total of 480 19 wk old Hy-Line W-36 Single Comb White Leghorn hens were weighed and randomly allocated to 6 replicate groups of 16 hens each (2 adjacent cages containing 8 hens per cage, 60.9×58.4 cm) per dietary treatment in a randomized complete block design. The hens were fed 5 treatment diets formulated to contain 85, 90, 95, 100, and 105% of the energy and nutrient recommendations stated in the 2009 Hy-Line Variety W-36 Commercial Management Guide. Production performance was measured for 52 wk from 19 to 70 wk age. Over the course of the trial, a significant increasing linear response to increasing energy and nutrient density was seen for hen-day egg production, egg weight, egg mass, feed efficiency, energy intake, and body weight (BW). Feed intake showed no significant linear level response to increasing energy and nutrient density except during the early production cycle. No consistent responses were noted for egg quality, percent yolk, and percent egg solids throughout the study. Significant linear responses due to energy and nutrient density were seen for egg income, feed cost, and income minus feed cost. In general, as energy and nutrient density increased, egg income and feed cost per hen increased, but income minus feed cost decreased. Overall, these results indicate that feeding Hy-Line W-36 hens increasing energy and nutrient-dense diets will increase egg production, egg weight, egg mass, feed efficiency, energy intake, BW, egg income, and feed cost, but decrease egg income minus feed cost. However, these benefits do not take effect in early production and seem to be most effective in later stages of the production cycle, perhaps "priming" the birds for better egg-production persistency with age.

No effect of short-term exposure to high-fibre diets on the gastrointestinal morphology of layer hens (Gallus gallus domesticus): body reserves are used to manage energy deficits in favour of phenotypic plasticity

Using layer hens, Gallus gallus domesticus, we compared the digestive capabilities of birds on a low-fibre diet (LF, 8.49% neutral detergent fibre; NDF), with those fed a high-fibre diet balanced for energy and protein to match the LF diet (high fibre balanced, HFB; NDF = 15.61%) and those fed a high fibre unbalanced (HFU) diet (NDF = 16.68%). The HFU diet had the lowest apparent dry matter (DM) metabolisability at 58.14 ± 6.46%, followed by HFB, 65.87 ± 3.50 and the LF diet, 70.49 ± 7.07%. Despite significant differences between apparent DM metabolisabilities of LF and HFU diets, no morphometric changes in the gastrointestinal tract (GIT) of layer hens were observed (including crop, gizzard, proventriculus, liver, large intestine, paired caeca and small intestine). Conversely, body mass losses were recorded for animals on HFU diet, while those on the LF and HFB diets actually gained body mass over the 14-day trials. We suggest that the body mass losses seen in the animals fed HFU diets were attributed to losses in adipose tissue, but this was not quantified. Assuming body mass losses were mainly in adipose tissue, we propose that adipose may act to buffer environmental challenges like shortfalls in nutrient acquisition when dietary energy requirements are not met. Compared with smaller birds (e.g. quail), the larger body size of the layer hens may offer them a greater safety margin in terms of body energy reserves before changes in the GIT might be needed to redress energy deficits associated with hard-to-digest, high-fibre diets.

Effects of nutrient dilution and nonstarch polysaccharide concentration in rearing and laying diets on eating behavior and feather damage of rearing and laying hens

An experiment was conducted with 768 non-cage-housed ISA Brown pullets, of which 576 hens were followed during the laying period, to investigate the separate effects of dietary energy dilution and non-starch polysaccharides (NSP) concentration (oat hulls as NSP source) on eating behavior and feather damage. Day-old pullets were allotted to 1 of 6 dietary treatments according to a 3 x 2 factorial arrangement (3 dilution and 2 NSP levels), with 8 replicates (pens) per treatment. At 17 wk of age, pens with hens were allotted to 1 of 8 dietary treatments according to a 4 x 2 factorial arrangement (4 dilution and 2 NSP levels), with 6 replicates per treatment. Compared with 0% dilution level, feed intake of laying hens of 10, 15, and 20% dilution levels increased by 8.4% (9.5 g/hen per d), 16.5% (18.1 g/hen per d), and 20.9% (23.6 g/hen per d), respectively. The ME(n) intake was similar for all dilution levels. Hens fed standard-NSP laying diets had similar insoluble NSP intake for all dilution levels (9.3 g/hen per d). Insoluble NSP intake of hens fed high-NSP laying diets increased from 15.6 g/hen per day (0% dilution) to 18.9 g/hen per day (20% dilution). Providing high- vs. standard-NSP layer diet decreased relative proventriculus contents (1.1 vs. 0.3 g/kg of BW) and increased empty gizzard weight (14.3 vs. 24.4 g/kg of BW). Hens that were fed standard-NSP diets had more feather damage compared with hens fed high-NSP diets (0.58 vs. 0.30 arbitrary units). Increasing the insoluble NSP intake resulted in decreased proventricular weight and increased gizzard weight and its contents, which are indicators of improved functioning of the gut, thereby linearly reducing feather damage. Providing diluted rearing diets increased feed intake from the first weeks of life onwards. It was hypothesized that pullets were increasingly "imprinted" on feed as pecking substrate if dilution level increased. This may decrease feather pecking and could explain the improved feather condition at 49 wk of age when 15% diluted rearing diet was fed.