Effects of selenium supplementation on the growth performance, slaughter characteristics, and blood biochemistry of naked neck chicken.

This study examined how selenium-supplemented diets affected the performance of naked neck chickens. The birds were fed both organic and inorganic selenium at 0.30 ppm, while the control diet did not include any additional selenium. A total of 225 one-day-old naked neck chicks were randomly divided into 3 experimental groups, each of which was replicated 5 times (replicates) and contained 15 birds. This was done using a completely randomized design. The data was collected after growth, meat quality, and blood profile parameters were assessed. The findings showed that the birds fed inorganic selenium in the diet displayed increased (P < 0.05) feed intake followed by those administered organic selenium and the control diet. On the other hand, birds fed organic selenium in the diet showed enhanced body weight gain and better feed conversion ratio (P < 0.05). Similarly, organic selenium supplementation increased (P < 0.05) breast and thigh weight compared to inorganic selenium, but no other metrics, such as dressing percentage, drumstick weight, liver weight, gizzard weight, heart weight, or wing weight, significantly differed between treatments (P > 0.05). When compared to birds fed inorganic Se and control diet, the birds fed organic Se had greater (P < 0.05) blood levels of total protein and globulin. Additionally, it was discovered that organic Se-fed birds had greater (P < 0.05) blood Se concentrations than control and inorganic Se-fed birds. However, no differences between treatments were found in albumin, glucose, cholesterol, triglycerides, or uric acid (P > 0.05). In conclusion, adding Se-enriched yeast, as an organic selenium source, to diets may enhance the poor growth and slaughter characteristics of naked neck chicks without negatively affecting blood chemistry.

Genotype by feeding regimen interactions for slaughter traits in rabbit and expected responses under restricted and full feeding.

The interaction between the genotype and feeding regimen (G×FR) for slaughter traits was estimated from data corresponding to 2557 animals under full (FF) and 2424 with restricted feeding (RF). Expected responses to selection under different scenario regarding feeding regimen were also calculated. Body weight at slaughter (SW), carcass weight (CW) and dressing out percentage (DoP) were analysed by using linear animal models in which records obtained under different feeding regimes were treated as different traits. Animals belonged to Caldes line, selected for average daily gain (G) under ad libitum feeding. The selection process information was included in the analyses. Marginal posterior mean of heritabilities were 0.102 for G, and 0.364, 0.257 and 0.167 for SW, CW and DoP under FF feeding. The corresponding values for animals fed on RF were 0.243, 0.203 and 0.379 for SW, CW and DoP, respectively. Genetic correlations between G and CW were positive and moderate, and those between G and DoP were low. The estimated genetic correlation between SW, CW and DoP under different feeding regimens were: 0.73, 0.69 and 0.87, respectively. These correlations cannot be said to be far enough from one to generate relevant G×FR interaction variance, which were estimated to be only 11.1%, 8.6% and 5.3% of the mean of the phenotypic variance for SW, CW and DoP, respectively. This lack of G×FR interaction variance, jointly with the higher heritability of DoP under RF, explains that the genetic improvement of DoP can be done more efficiently recording traits on animals under RF, even if the interest is on the performances under FF, i.e. by indirect selection.

Comparison and analysis on sheep meat quality and flavor under pasture-based fattening contrast to intensive pasture-based feeding system.

OBJECTIVE: The objective of this study was to investigate the effect of 4-month intensive feeding on the meat quality, fatty acid profile, flavor, and growth performance of grazing Hulunbuir sheep (HBS). METHODS: The HBS were selected 4-months after birth in a pasture rearing system as the experimental animals (n = 44, female, average body weight 23.8±2.2 kg) then divided equally into pasture-based grazing fattening (PAS) and concentrate-included intensive fattening (CON) groups for another 4-month finishing. When finished fattening, all animals were slaughtered to collect musculus longissimus dorsi subcutaneous adipose tissue and to investigate the influences on meat quality, fatty acid profile, flavor and growth performance. RESULTS: The results showed lambs in CON group got significantly higher live weight, hot carcass weight, and dressing percentage. The CON group had significantly higher value of redness (a*), lightness (L*) and water holding capacity (p<0.05), significantly lower value of Warner-Bratzler shear force than the PAS group (p<0.05). The subcutaneous fat from CON group lambs demonstrated a significantly higher content of C18:1 and C18:2 (p<0.05), but lower C14:0 and C16:0, indicating an increased degree of unsaturated fatty acid. The content of 4-methyloctanoic acid, 4-ethyloctanoic acid and 4-methylnonanoic acid had increased 2 to 4 times, representing a more intense odor in the CON group. However, the values were still lower than most sheep breeds reported, indicating the indoor feeding system could not fundamentally deteriorate the excellent meat characteristic of HBS. CONCLUSION: It was evident that lambs in CON group exhibited a better meat production performance, improved in meat color, texture and healthier fatty acid profile through pastureweaned concentrate included intensive fattening system, which offers a good alternative regimen for lamb finishing and has a wide prospection in the HBS meat industry.

Estrategia de cruzamientos para el mejoramiento de pollos Camperos. Un proyecto colaborativo INTA-universidad / Crossing strategy for breeding Campero chickens. An INTA-university collaborative project

RESUMEN El pollo campero es un ave destinado a sistemas productivos alternativos al industrial. Campero INTA es un cruzamiento simple entre poblaciones sintéticas generadas por INTA en Pergamino. Estas poblaciones se han mantenido cerradas y con bajo tamaño efectivo con el consiguiente efecto detrimental asociado a fenómenos de depresión endogámica. Con el objetivo de disponer de una población doble propósito con adecuados niveles productivos de carne y huevos y de rusticidad para ser utilizada en sistemas semi-intensivos que preservan el bienestar animal, se implementó un programa de relevamiento del recurso genético disponible y se diseñó un plan de cruzamientos dirigido a la producción de un híbrido terminal de tres vías. La secuencia incluyó la evaluación de cinco poblaciones sintéticas maternas (A, E, DE, ES y CE), la selección de dos de ellas (ES y A), su caracterización en cruzamientos simples recíprocos [(ESxA) y (AxES)], la elección de la alternativa (ESxA) como progenitor femenino y su cruzamiento por gallos de la estirpe paterna mejorada AH' para la obtención como producto final del pollo Campero Casilda. La evaluación de su patrón de crecimiento, conformación corporal, relación de conversión y caracteres productivos a la faena indican que tanto los machos como las hembras cumplen, como aves destinadas a la producción de carne, con las exigencias establecidas en el protocolo respectivo. La evaluación de los caracteres productivos a la madurez sexual, el patrón dinámico de aumento de peso del huevo y las curvas de postura califican a las hembras para su utilización como ponedoras.

ABSTRACT Campero chicken is a bird destined to production systems alternative to the industrial one. Campero INTA is a two-way cross between synthetic populations generated by INTA in Pergamino. These populations have remained closed and with a low effective size with the consequent detrimental effect associated with inbreeding depression. To have a dual-purpose population with adequate meat and egg production levels and rusticity to be used in semi-intensive systems that preserve animal welfare, a survey program of the available genetic resource was implemented and a crossbreeding plan to produce a terminal three-way hybrid was designed. The sequence included the evaluation of five maternal synthetic populations (A, E, DE, ES and CE), the selection of two of them (ES and A), their characterization in two-way reciprocal crosses [(ESxA) and (AxES)], the choice of the alternative (ESxA) as female parent and its crossing by roosters of the improved paternal line AH' to obtain the Campero Casilda chicken as the final product. The evaluation of their growth pattern, body conformation, conversion ratio and productive characters at slaughter indicate that both males and females satisfied the requirements as birds destined for meat production established in the respective protocol. The evaluation of productive characters at sexual maturity, dynamic pattern of egg weight gain and laying curves allowed to qualify the females as layers.

Effect of a Diet Supplemented with Nettle (Urtica dioica L.) or Fenugreek (Trigonella foenum-graecum L.) on the Post-Slaughter Traits and Meat Quality Parameters of Termond White Rabbits.

The purpose of the study was to analyse the effect of nettle (Urtica dioica L.) leaves and fenugreek (Trigonella foenum-graecum L.) seeds as additives to fodder in order to improve post-slaughter traits and quality parameters of Termond White rabbit meat (n = 60; 30♂, 30♀). Three experimental groups were created. The control group (n = 20; 10♂ and 10♀) was fed ad libitum feed containing corn, bran, wheat, dried alfalfa, soybean meal, sunflower meal, dicalcium phosphate, calcium carbonate and vitamin-mineral premix. The animals from the first experimental group (n = 20; 10♂ and 10♀) were fed a complete mixture added with 1% of nettle (Urtica dioica L.) leaves. Rabbits from the second group (n = 20; 10♂ and 10♀) were fed with a complete mixture added with 1% of fenugreek (Trigonella foenum-graecum L.) seeds. Rabbits fed with pellets with the addition of nettle were characterized by a higher slaughter weight, higher weight of hot and cold carcasses, lungs, kidneys and head as well as a higher weight of the fore, middle and hind part of the carcass compared to the other two groups. The carcasses of animals fed with fenugreek and nettle had a higher percentage of the fore and hind parts compared to the carcasses of the animals from the control group. The female carcasses were characterized by a significantly higher percentage of the middle part compared to the male carcasses. For most colour measurement traits, the differences depending on the feeding regime were significant. The effect of gender on meat colour was non significant. The effect of feeding regime and of gender on texture traits such as shear force, hardness, springiness, cohesiveness and chewiness were non significant. Feeding had no effect on muscle fibre diameter, but it affected the muscle fibre type I percentage. Thus, the group fed with pellets containing nettle leaves had higher percentage of type I muscle fibres than the control group. The effect of gender on muscle fibre traits was non significant.

Effect of ambient temperature on the productive and carcass traits of growing rabbits divergently selected for body fat content.

Rabbits are particularly sensitive to heat stress which can affect productive performance, with rabbit breed/line possibly playing a role on the response to this condition. The study aimed at evaluating the effect of different ambient temperatures on the live performance and carcass traits of growing rabbits divergently selected for total body fat content. The two genetic lines (Lean and Fat) were selected based on the total body fat content estimated by computer tomography during five generations. From birth to slaughter (13 weeks of age), the rabbits were housed in two rooms where the temperature was controlled with air conditioners: in the control room the average ambient temperature was 20 °C and in the high temperature room it was 28 °C. After weaning (35 d), 60 Lean and 60 Fat rabbits/room were housed by two in wire-mesh cages and fed ad libitum with commercial pellets. The BW and feed intake (FI) were measured at 5, 7, 9, 11 and 13 weeks of age to calculate the daily weight gain (DWG) and feed conversion ratio (FCR). Mortality was recorded daily. At the end of the experiment, rabbits were slaughtered and carcass traits were measured. Mortality was independent of temperature and line. The temperature significantly influenced the FI, DWG, BW and the fat deposits: they were lower at higher ambient temperature. The effect of temperature differed according to the rabbits' total body fat content. At control temperature, the FI (165 vs 155 g/day; P < 0.05) and FCR (4.67 vs 4.31; P < 0.05) were higher in Fat rabbits, which also had more perirenal (36.2 vs 23.1 g; P < 0.05) and scapular fat (10.8 vs 7.1 g; P < 0.05). At high temperature, no differences in fat depots (14.5 vs 9.8 g; 5.3 vs 3.5 g) were found between the two lines. It can be concluded that temperature × genetic line interaction had an important role in productive and carcass traits, as the effect of temperature differs between Lean and Fat rabbits.

Calm Hu ram lambs assigned by temperament classification are healthier and have better meat quality than nervous Hu ram lambs.

The objective of this study was to evaluate the effects of temperament classification (assessed using an arena test) on health and productivity of Hu ram lambs. In experiment one, eight ram lambs classified as calm and eight classified as nervous (selected from 100 ram lambs) were fed individually for 60-days to compare food intake, food digestibility, weight gain, and biochemical indices of health. In experiment two, nine ram lambs classified as calm and nine classified as nervous (selected from 150 ram lambs) were fed in a group and slaughter traits, meat quality, and muscle histology were compared. Calm lambs had higher dry matter digestibility, lower serum TNF-α, higher total antioxidant capacity, higher total superoxide dismutase activity, higher dressing percentage, higher cross-sectional area of loin, higher myofibre density, lower ultimate pH of the meat, and higher meat redness, than nervous lambs. Selection for calm temperament could be beneficial to health, slaughter, and carcass traits in Hu ram lambs.

Feed efficiency and carcass metrics in growing cattle1.

Some definitions of feed efficiency such as residual energy intake (REI) and residual gain (RG) may not truly reflect production efficiency. The energy sinks used in the derivation of the traits include metabolic live-weight; producers finishing cattle for slaughter are, however, paid on the basis of carcass weight, as opposed to live-weight. The objective of the present study was to explore alternative definitions of REI and RG which are more reflective of production efficiency, and quantify their relationship with performance, ultrasound, and carcass traits across multiple breeds and sexes of cattle. Feed intake and live-weight records were available on 5,172 growing animals, 2,187 of which also had information relating to carcass traits; all animals were fed a concentrate-based diet representative of a feedlot diet. Animal linear mixed models were used to estimate (co)variance components. Heritability estimates for all derived REI traits varied from 0.36 (REICWF; REI using carcass weight and carcass fat as energy sinks) to 0.50 (traditional REI derived with the energy sinks of both live-weight and ADG). The heritability for the RG traits varied from 0.24 to 0.34. Phenotypic correlations among all definitions of the REI traits ranged from 0.90 (REI with REICWF) to 0.99 (traditional REI with REI using metabolic preslaughter live-weight and ADG). All were different (P < 0.001) from one suggesting reranking of animals when using different definitions of REI to identify efficient cattle. The derived RG traits were either weakly or not correlated (P > 0.05) with the ultrasound and carcass traits. Genetic correlations between the REI traits with carcass weight, dressing difference (i.e., live-weight immediately preslaughter minus carcass weight) and dressing percentage (i.e., carcass weight divided by live-weight immediately preslaughter) implies that selection on any of the REI traits will increase carcass weight, lower the dressing difference and increase dressing percentage. Selection on REICW (REI using carcass weight as an energy sink), as opposed to traditional REI, should increase the carcass weight 2.2 times slower but reduce the dressing difference 4.3 times faster. While traditionally defined REI is informative from a research perspective, the ability to convert energy into live-weight gain does not necessarily equate to carcass gain, and as such, traits such as REICW and REICWF provide a better description of production efficiency for feedlot cattle.

Genetic parameters and genome-wide association study regarding feed efficiency and slaughter traits in Charolais cows.

Residual energy intake (REI) on two successive diets (hay and maize based) and slaughter traits, including visceral organs, were phenotyped in 584 adult purebred Charolais cows. To investigate the relationships between these traits and their genetic determinism, we first estimated the genetic parameters, including correlations, using REML modeling under WOMBAT software. The animals were then genotyped on the BovineSNP50 SNPchip before being imputed to the 600K density and genome wide association study was performed with GCTA software. We found low heritability for REI (h2 = 0.12 in each of the diet phases). Although the phenotypic correlation between the two diet phases was moderate (0.36), the genetic correlation was high (0.83), indicating a common genetic determinism for feed efficiency regardless of the diet. Correlations between REI and slaughter traits were negative regarding muscle-related traits and positive for fat-related traits, indicating that efficient animals generally had a more muscular carcass. It was also seen that feed efficiency was genetically and phenotypically correlated with smaller organs when expressed as a proportion of their empty body weight. From the GWAS analysis, seven QTLs were found to be associated with a trait at the genome-wide level of significance and 18 others at the chromosome-wide level. One important QTL was detected in BTA 2, reflecting the essential effect of the myostatin gene on both carcass composition and relative organ weight. Three QTLs were detected for REI during the maize diet phase on BTA 13, 19, and 28, the latter being significant at the genome-wide level. The QTLs on BTA 19 mapped into the TANC2 gene and the QTLs on BTA 28 into the KIF1BP gene, which are both known to interact with the same protein (KIF1A). However, no obvious functional link between these genes and feed efficiency could be made. Among the other QTLs detected, one association on BTA 4 with liver proportion mapped to the candidate gene WASL, which has previously been shown to be differentially expressed in liver cells and linked to feed restriction or cancer development. No QTLs were found to be common between feed efficiency and any slaughter traits.

Effects of water supplementation of an organic acid-trace mineral complex on production and slaughter parameters, intestinal histomorphology, and macronutrient digestibility in growing ostriches.

An experiment was conducted to study the effect of water supplementation of organic acid-chelated trace minerals (OTM) on production traits, carcass characteristics, intestinal histomorphology, and nutrient digestibility in African ostrich chicks from 8 to 12 mo of age. A total of 20 growing ostriches, with almost similar body weight (73.4 to 75.8 kg), were individually distributed in outdoor paddocks of ≈ 24 m2 and were randomly allocated into 1 of the following 4 treatments: (1) control/basal diet, (2) low OTM (basal diet + 100 mg/bird/day OTM powder in water), (3) medium OTM (basal diet + 1 g/bird/day OTM powder in water), and (4) high OTM (basal diet + 2 g/bird/day OTM powder in water). The body weight gain and feed conversion efficiency were greater (P < 0.05) in ostriches receiving medium-OTM treatment compared to control during the overall phase of the experiment. Although whole carcass yield, the yield of parts, and the relative weights of internal organs were not affected by experimental treatments, supplementation of higher amounts of OTM (medium- and high-OTM) resulted in a decrease (P < 0.05) in the subcutaneous and abdominal fat contents. Medium- and high-OTM treatments increased (P < 0.05) the villus height/crypt depth ratio in the jejunum and ileum compared with control and low-OTM treatments. Moreover, ostriches receiving the medium-OTM had also higher total tract apparent digestibility of energy (P = 0.048), ether extract (P = 0.050), crude fiber (P = 0.063), and higher AMEn (P = 0.094) than the control group. Overall, supplementation of OTM at the level of 1 g/bird/day to the drinking water of growing ostriches fed diets containing the recommended levels of inorganic trace minerals could beneficially affect productive performance, nutrient digestibility, and intestinal morphology.

Relationship between feed efficiency and slaughter traits of French Charolais bulls.

Improving feed efficiency is of interest to French beef producers so as to increase their profitability. To enable this improvement through selection, genetic correlations with production traits need to be quantified. The objective of this study was to estimate the genetic parameters for growth, feed efficiency (FE), and slaughter performance of young beef bulls of the French Charolais breed. Three feed efficiency criteria were calculated: residual feed intake (RFI), residual gain (RG), and ratio of FE. Data on feed intake, growth, and FE were available for 4,675 Charolais bulls tested in performance test stations and fed with pelleted diet. Between 1985 and 1989, 60 among 510 of these bulls were selected to procreate one generation of 1,477 progeny bulls which received the same pelleted diet at the experimental farm in Bourges. In addition to feed intake, growth, and FE traits, these terminal bulls also had slaughter traits of carcass yield, carcass composition, and weight of visceral organs collected. Genetic parameters were estimated using linear mixed animal models. Between performance test bulls and terminal bulls, the genetic correlation of RFI was 0.80 ± 0.18; it was 0.70 ± 0.21 for RG and 0.46 ± 0.20 for FE. For carcass traits, RFI was negatively correlated with carcass yield (-0.18 ± 0.14) and muscle content (-0.47 ± 0.14) and positively with fat content (0.48 ± 0.13). Conversely, RG and FE were positively correlated with carcass yield and muscle content and negatively with fat content. For the three FE criteria, efficient animals had leaner carcass. For visceral organs (as a proportion of empty body weight), RFI was genetically correlated with the proportions of the 5th quarter (0.51 ± 0.17), internal fat (0.36 ± 0.14), abomasum (0.46 ± 0.20), intestines (0.38 ± 0.17), liver (0.36 ± 0.16), and kidneys (0.73 ± 0.11). Conversely, RG and FE were negatively associated with these traits. The high-energy expenditure associated with the high-protein turnover in visceral organs may explain this opposite relationship between FE and the proportion of visceral organs. Selection for final weight and RFI increased growth and FE in progeny, and also improved carcass yield and muscle content in the carcass. To conclude, determinations of growth and feed intake in performance test stations are effective to select bulls to improve their growth, FE, and muscle content in carcass.

Organic Selenium, Probiotics, and Prebiotics Effects on Growth, Blood Biochemistry, and Carcass Traits of Growing Rabbits During Summer and Winter Seasons.

The effect of organic selenium, prebiotics, or probiotics on productive performances, blood biochemistry, and carcass characteristics of growing rabbits was studied throughout summer and winter seasons. In an 8-week feeding trial, a total of 100 New Zealand White rabbits were randomly distributed to 10 groups. Two seasons (winter and summer) and five diets fortified with 0 (control), 0.03 mg selenium, 3 g Bio-Mos®, 1 g Bactocell® (1 × 1010 CFU) or 3 g yeast/kg diet were used in 2 × 5 factorial design. Results indicated that growth performance, feed intake (FI), and blood components (red blood cells [RBCs], serum total protein [TP], globulin [GLOB], albumin [ALB]) decreased significantly in rabbits reared during summer than in those during winter. In contrast, white blood cells, urea-N, creatinine, alanine transaminase [ALT], and aspartate transaminase [AST] increased significantly in summer. However, growth performance indices, FI, blood hemoglobin, RBCs, TP, ALB, and GLOB increased significantly in rabbits when fed the tested feed additives. The respiration rate, rectal temperature, and heart rate of the animals were significantly decreased with all feed additives. Adjusted weight of carcass, liver, kidney fat, and carcass cuts were not affected by feed additives. Final margin and margin efficiency increased in rabbit fed diets supplemented with feed additives than those fed the basal diet without any supplementation. Results of the current study concluded that a supplementation of rabbit diets with organic selenium, probiotics, and prebiotics can promote rabbit performance during mild weather and also alleviate the adverse impact of heat stress during summer season.