Comparative Impact of Hydroxychloride and Organic Sources of Manganese, Zinc, and Copper in Rearing Diets on Pullet Growth, Tibia Traits, Egg Production, and Eggshell Quality in Lohmann Brown Birds up to 50 Weeks of Age.

(1) Background: This study assessed the efficacy of hydroxychloride sources of zinc (Zn), manganese (Mn), and copper (Cu) compared with organic sources in the rearing diets of Lohmann brown pullets, focusing on pullet performance, tibia quality, egg production, and eggshell quality. (2) Methods: A total of 120 birds (six replications and 10 birds each) received diets with Mn, Zn, and Cu from organic or hydroxychloride sources during the rearing phase. After the onset of lay, birds were fed diets containing oxide/sulfate sources up to 50 weeks of age. (3) Results: no significant differences were observed in growth performance and tibia quality during the rearing phase (p > 0.05). From 18 to 24 weeks of age, no carryover effect on egg production performance was observed. However, from 25-50 weeks, pullets fed hydroxychloride sources showed lower feed intake and egg mass compared to the organic group (p < 0.05), whereas egg production and eggshell quality remained similar between groups (p > 0.05). (4) Conclusions: These findings suggest the potential of hydroxychloride sources in rearing diets without compromising overall growth in the pullet phase and feed efficiency in the laying cycle.

Application of bioelectrical impedance analysis to assess body composition of male and female broiler chickens from 2 different strains throughout the growth period.

Bioelectrical impedance analysis (BIA) was performed in males and females of 2 different broiler strains from 0 to 42 d of age to develop and validate equations to predict body composition (BC). A total of 528 birds, 132 birds per sex and strain (Ross 308 and Cobb 500) were used in the experiment. Birds were fed ad libitum following CVB recommendations with a common starter (0-14 d), grower (15-29 d), and finisher diet (30-42 d). Bioelectrical impedance analysis was measured weekly from 0 to 42 d. Birds were euthanized, frozen and ground for sample collection. Each sample was analyzed through proximate analysis for dry matter (DM), protein, fat, ash, and energy content. Water (%), protein and ash (% DM) decreased with age (77.5-67.5, 69.1-52.2, and 8.12-7.29, respectively; P < 0.0001); whereas fat (% DM) and energy (cal/g DM) increased with the age (20.7-36.4 and 5,421-6151, respectively; P < 0.0001). Males had significantly higher water (%) and protein (% DM) contents, and lower lipid (% DM) deposits than females (70.5, 55.5, and 32.6 vs. 69.6, 54.6, and 33.7, respectively; P < 0.0001). Cobb 500 had a higher fat and lower protein (% DM) and water (%) content than Ross (34.6, 54.0, and 69.7 vs. 31.7, 56.1, and 70.4, respectively; P < 0.0001). A multiple linear regression analysis was carried out to select the equation model to predict BC using the relative mean prediction error (RMPE, %) to evaluate the accuracy. The coefficients of determination (R2) to estimate water (%), protein, fat, ash (% DM) and energy content (cal/g DM) were 0.909, 0.825, 0.795, 0.493, and 0.838, respectively, and the RMPE were 1.26, 3.46, 7.73, 8.85, and 1.86%, respectively. A t test analysis was run, observing no differences in any of the parameters under study between the analyzed and estimated values. Based on these results, we can conclude that BIA can be used as a valid non-invasive technique to estimate in vivo BC in broilers.

The impact of digestible lysine and sulfur amino acids on eggshell quality and egg weight control in old ISA brown hens during 62 to 74 wk.

Modifying dietary amino acids has been proposed as a strategy to improve eggshell quality by slowing down increases in egg weight (EW). This study aimed to investigate the effects of different levels of digestible lysine (dLYS) and ratios of digestible sulfur amino acids (dTSAA) to dLYS on performance and eggshell quality in ISA brown hens. A total of 288 hens were individually housed and assigned to 8 treatments, which combined 2 levels of dLYS (5.9 and 5.5 g/kg) with 4 ratios of dTSAA:dLYS (90, 85, 80, and 75) in a factorial arrangement. The study lasted 12 wk, starting at 62 wk of age. The number of eggs was not affected by the interaction between dLYS and dTSAA:dLYS or their main effect. However, the interaction between dLYS and dTSAA:dLYS showed that reducing the dTSAA:dLYS ratio from 85 to 75 when hens were fed 5.5 g/kg of dLYS resulted in a lower EW. Conversely, when hens were fed 5.9 g/kg of dLYS, no significant difference was found in EW among the different ratios of dTSAA:dLYS. Although there was no interaction between the levels of dLYS and dTSAA:dLYS on eggshell quality, reducing the dLYS level from 5.9 to 5.5 slowed down the deterioration in eggshell-breaking strength and eggshell thickness, regardless of the dTSAA:dLYS ratio. These findings suggest that adjusting dietary dLYS while maintaining the dTSAA:dLYS ratio of no less than 85 may be an effective strategy for decelerating the deterioration of eggshell quality in laying hen operations without impacting the egg production rate.

Application of Bioelectrical Impedance Analysis (BIA) to Assess Carcass Composition and Nutrient Retention in Rabbits from 25 to 77 Days of Age.

The aim of this study was to assess and validate, using independent data, the prediction equations obtained to estimate in vivo carcass composition using bioelectrical impedance analysis (BIA) to determine the nutrient retention and overall energy and nitrogen retention efficiencies of growing rabbits. Seventy-five rabbits grouped into five different ages (25, 35, 49, 63 and 77 days) were used in the study. A four-terminal body-composition analyzer was applied to obtain resistance (Rs, Ω) and reactance (Xc, Ω) values. All the animals were stunned and bled at each selected age, and the chilled carcasses were analyzed to determine water, fat, crude protein (CP), ash and gross energy (GE). Multiple linear regression analysis was conducted to determine the equations, using body weight, length and impedance data as independent variables. The coefficients of determination (R2) to estimate the content of water, protein, fat and ash in grams, and energy in Mega Jules(MJ), were: 0.99, 0.99, 0.95, 0.96 and 0.98, respectively, and the relative mean prediction errors (RMPE) were: 4.20, 5.48, 21.9, 9.10 and 6.77%, respectively. Carcass yield (%) estimation had values of 0.50 and 10.0 for R2 and RMPE, respectively. When water content was expressed as a percentage, the R2 and RMPE were 0.79 and 1.62%, respectively. When the protein, fat and ash were expressed as a percentage of dry matter (%DM) and the energy content as kJ/100 g DM, the R2 values were 0.68, 0.76, 0.66 and 0.82, respectively, and the RMPEs were 3.22, 10.5, 5.82 and 2.54%, respectively. Energy Retention Efficiency was 20.4 ± 7.29%, 21.0 ± 4.18% and 20.8 ± 2.79% from 35 to 49, from 49 to 63 and from 35 to 63 d, respectively. Nitrogen Retention Efficiency was 46.9 ± 11.7%, 34.5 ± 7.32% and 39.1 ± 3.23% for the same periods. Energy was retained in body tissues for growth with an efficiency of approximately 52.5%, and the energy efficiency for protein and fat retention was 33.3 and 69.9%, respectively. This work shows that BIA is a non-invasive and good method to estimate in vivo carcass composition and to determine the nutrient retention of growing rabbits from 25 to 77 days of age.

Hydroxychloride trace minerals have a positive effect on growth performance, carcass quality and impact ileal and cecal microbiota in broiler chickens.

BACKGROUND: The objective was to study the effect of hydroxychloride trace minerals (HTM) on growth performance, carcass quality and gut microbiota of broiler chickens in comparison to sulphate trace minerals (STM). In total 1440 male Ross 308 day-old chicks were divided into 12 replicate pens with 30 birds each per treatment. Four different treatments were tested according to a 2 × 2 factorial study design, where the animals received a three phase diet containing either inorganic Zn from sulphates or Zn from HTM in high (80 mg/kg Zn) or low Zn dosage (20 mg/kg Zn). In all treatments 15 mg/kg Cu was added from the same mineral source as the Zn. Body weight and feed intake were measured on day 0, 10, 27 and 34, while carcass and breast meat yields were measured at the end of the study (day 34). In addition, high-throughput sequencing analysis was performed in digesta samples from ileum and cecum to study the gut microbiome (day 34). RESULTS: The results showed an improved (P < 0.05) body weight of broiler chickens fed HTM, regardless of Zn level, on day 27, while on day 34 this effect remained as a tendency (P = 0.0542). In the overall study period, birds fed HTM had a higher (P < 0.05) average daily gain and average daily feed intake when compared to birds fed STM. The mineral source did not affect the carcass characteristics, however, feeding 80 mg/kg Zn resulted in a significantly higher (P = 0.0171) breast meat yield, regardless of source. High-throughput sequencing analysis of the microbiota revealed a higher microbial diversity in the ileum and cecum of HTM fed birds compared to STM fed birds. Taxonomical differences were mainly found in the cecum, specifically between the group fed high and low Zn levels from HTM. This correlated with the mineral contents observed in the cecal digesta. Comparing both groups fed 80 mg/kg Zn, the HTM group had more Streptococcaceae, Streptococcus, Clostridia, Weissella and Leuconostocaceae compared to the STM group. CONCLUSIONS: HTM improved growth performance of broiler chickens; and the source and level of Zn modulated the gut microbiota communities in broilers differentially.

Relationship between Bone Quality, Egg Production and Eggshell Quality in Laying Hens at the End of an Extended Production Cycle (105 Weeks).

(1) Background: Nowadays the industry aims to improve lay persistency for extended cycles (100 weeks or longer) to make egg production more sustainable. However, intensive egg production challenges hen health, inducing severe osteoporosis and the incidence of bone fractures. In this study, the relationship between bone quality and egg production, and/or eggshell quality, was evaluated at the end of an extended laying cycle of 100 weeks, comparing groups of hens with different production and eggshell quality parameters; (2) Methods: Quality parameters of egg (as weight, egg white height), eggshell (as thickness, weight, breaking strength, elasticity and microstructure) and tibiae bone (weight, diameter, cortical thickness, ash weight, breaking strength, medullary bone) were determined; (3) Results: Hens from groups with a high egg production and good eggshell quality have poorer bone quality (lower ash weight and lesser amount of medullary bone). However, Pearson's correlation analysis shows no clear relationship between bone and egg/eggshell parameters. (4) Conclusions: Bone and egg production/eggshell quality are independent and can be improved separately. Medullary bone has an important contribution to bone mechanical properties, being important to accumulate enough bone medullary bone early in life to maintain skeletal integrity and eggshell quality in old hens.