Slaughter Traits Research Articles

Effect of guanidinoacetic acid on the growth performance, myofiber, and adenine nucleotide of meat-type rabbits.

This study aimed to investigate the effect of dietary guanidinoacetic acid (GAA) on the growth performance, slaughter traits, myofiber, and adenine nucleotide of meat-type rabbits. Experimental treatments consisted of control (CON) and GAA addition at 0.04% (T1), 0.08% (T2), and 0.12% (T3) of diet. A total of 240 weaned rabbits (meat-type male Chinese black rabbits) were randomly distributed into four groups with six replicates of ten rabbits each. Results showed that the three doses of GAA increased (p<0.05) final body weight, carcass weight, the density and area of quadriceps femoris fiber; and T3 showed significant effects (p<0.05) on weight gain, feed/gain, and dressing percentage, and the traits of longissimus fiber, compared to CON. Dietary GAA increased (p<0.05) the meat color a* and b* in longissimus and quadriceps; and T3 showed the lowest (p<0.05) shear force of longissimus. Furthermore, GAA increased (p<0.05) the contents of adenosine triphosphate and total adenine nucleotide in longissimus and quadriceps. In longissimus adenosine triphosphate, total adenine nucleotide, and adenylate energy charges, T3 treatment was most effective (p<0.05); while T2 and T3 treatment was more effective (p<0.05) than T1 in quadriceps. Additionally, linear or quadratic responses (p<0.05) to the increased doses of GAA were found on body weight gain, meat color, total adenine nucleotide, and adenylate energy charges. It is concluded that GAA can be used in the rabbit diet to improve growth and carcass traits, and these are related to the high levels of muscle adenine nucleotide.

Productive Performances of Slow-Growing Chicken Breeds and Their Crosses with a Commercial Strain in Conventional and Free-Range Farming Systems.

Local chicken breeds play a vital role in promoting sustainability by preserving genetic diversity, enhancing resilience, and supporting local economies. These breeds are adapted to local climates and conditions, requiring fewer external resources and inputs for their maintenance. By conserving and utilizing local chicken breeds, sustainable farming practices can be incentivized, maintaining ecosystem balance and ensuring food security for future generations. The present study aimed at evaluating the growth performance and slaughter traits of two local Italian chicken breeds (Bionda Piemontese and Robusta Maculata) and their crosses with a medium-growth genotype (Sasso chicken®) reared in conventional and free-range farming systems. The conventional system used a high-energy high-protein diet in a closed barn with controlled temperature, humidity, and lighting, and a stocking density of 33 kg/m2. The free-range system used a low-input diet (low-energy low-protein diet composed of local and GMO-free feed ingredients), uncontrolled environmental conditions, and a stocking density of 21 kg/m2 in a barn with free access to an outdoor area. The birds were slaughtered at 84 days of age in both systems. The crossbred chickens showed the best results for growth performance in both farming systems compared to local breeds. Within genotype, the final live weight of chickens was similar in the two farming systems. In conclusion, slow-growth crossbreeds should be used in alternative farming systems, demonstrating better performance than pure local breeds.

Genetic (co)variance components for slaughter traits in a multi-breed sheep population.

Carcass value is one of the main contributors to revenue in meat sheep enterprises, while age at slaughter is also a major component to the cost of production. Despite the contribution of such traits to overall profit, little is actually known on the extent of exploitable genetic variability in the traits that govern carcass value (i.e. carcass weight, carcass conformation, carcass fat) and age at slaughter, especially independent of each other. The objective of the present study was to estimate genetic (co)variances for and among carcass weight, carcass conformation, carcass fat, kill-out percentage and age at slaughter as well as their genetic (co)variances with traits measured earlier in life. Data consisted of slaughter records from 15714 lambs, with 12630 of these lambs having at least one live weight measure. The heritability (SE) of carcass weight, carcass conformation, carcass fat, kill-out percentage, and age at slaughter was 0.14 (0.02), 0.19 (0.02), 0.08 (0.01), 0.22 (0.03), and 0.16 (0.02), respectively. The maternal heritability for age at slaughter was 0.07 (0.02); no maternal genetic influence was found on any of the other slaughter traits. The coefficient of genetic variation for carcass weight and age at slaughter was 3 and 8%, respectively. The correlations between the direct genetic effects for live weight throughout life, and carcass weight were weak up to weaning but were strong (0.83) thereafter. The correlation between the direct genetic effects of birth weight and age at slaughter was zero, but varied from -0.91 to -0.56 between live weight measured later in life and age at slaughter. Results demonstrate significant exploitable genetic variability in a range of slaughter traits with the prediction of genetic merit for carcass traits and age at slaughter being possible using live weight measures taken on live animals. For example, the accuracy of selection for slaughter traits (comprising of age at slaughter, carcass conformation and carcass fat) from weaning weight records available on 100 progeny was 0.37; when slaughter data were also available for 10 progeny, the accuracy of selection increased to 0.56.

Effect of TG5 and LEP polymorphisms on the productivity, chemical composition, and fatty acid profile of meat from Simmental bulls.

Enhancing the nutritional and biological value of meat obtained from young surplus replacement animals of dual-purpose breeds is a critical objective in the livestock industry. This study aimed to investigate the impact of thyroglobulin (TG5, c. -422C > T) and leptin (LEP, c. 239C > T) polymorphisms on the productivity, chemical composition, and fatty acid (FA) profile of meat from Simmental bulls. A total of 26 Simmental bulls were genotyped for TG5 (c. -422C > T) and LEP (c. 239C > T) polymorphisms and reared under the same fattening conditions. Controlled slaughter was conducted at 18 months of age. Subsequently, the experimental animals were evaluated to determine their slaughter traits and the chemical and FA composition of ground beef and the longissimus dorsi muscle. The results showed that the TG5 (c. -422C > T) polymorphism significantly (p < 0.05) affected the differentiation of bulls in terms of the synthesis of stearic acid, linolenic acid, and total polyunsaturated FAs, as well as the fat and dry matter content in the longissimus dorsi muscle. Conversely, the presence of the T allele in the LEP (c. 239C > T) polymorphism was associated with increased dry matter and fat in ground beef, carcass weight, and internal fat weight. The analysis of slaughter traits and the chemical and FA composition of meat from the Simmental bulls genotyped for the TG5 and LEP genes revealed a genetic basis for the quantitative and qualitative characteristics of meat productivity. Thus, the genetic variability of bulls regarding the LEP and TG5 genes can be used to improve the quantitative and qualitative indicators of meat productivity in Simmental cattle through marker-assisted selection.

Tryptophan improves antioxidant capability and meat quality by reducing responses to stress in nervous Hu sheep

In sheep, the effect of tryptophan (Trp) on behavioural traits that are associated with temperament and any effects on production traits is unknown. The hypothesis of this study is that the supplementation of Trp would improve temperament by enhancing serotonin production, which is beneficial to meat production subsequently in sheep. Twelve ewes that had the lowest and 12 ewes that had the highest behavioural responses to human contact were selected into the calm and the nervous groups respectively. Then, the ewes from each group were equally assigned into two treatments that were treated with the basal diet and the diet with extra 90 mg/kg/d Trp for 30 d. The temperament traits, the growth performance, the biochemicals that are related to health the slaughter performance and meat quality were measured at the end of feeding experiment. The findings in this study suggested the Hu sheep with calm temperament would experience less stress during production, resulting in less oxidative stress, better growth performance, slaughter traits and carcass traits, compared to the nervous sheep. Meanwhile, the dietary supplementation of Trp reduced stress responses by enhancing production of 5-HT in sheep from the nervous group which is beneficial to improve the production traits that mentioned above.

The effect of dietary L-carnitine and fat on performance, carcass traits and blood components in broiler chickens

Abstract The poultry industry has traditionally been selecting animals for improved performance without consideration for the effect on fat deposition. Dietary L-carnitine can alter lipid metabolism; nevertheless, when combined with fat, the effects are not clear. This study shows the effect of different dietary levels of L-carnitine (0, 200 and 400 mg/kg) and fat (0, 2.5 and 5%) on growth performance and slaughter traits of commercial broilers (Ross 308; n=270). The groups received the following dietary treatments: 1) 0 mg/kg L-carnitine + 0% fat, 2) 200 mg/kg L-carnitine + 0% fat, 3) 400 mg/kg L-carnitine + 0% fat, 4) 0 mg/kg L-carnitine + 2.5% fat, 5) 200 mg/kg L-carnitine + 2.5% fat, 6) 400 mg/kg L-carnitine + 2.5% fat, 7) 0 mg/kg L-carnitine + 5.0% fat, 8) 200 mg/kg L-carnitine + 5.0% fat, and 9) 400 mg/kg L-carnitine + 5.0% fat. Feed conversion ratio, growth performance, blood biochemical parameters, carcass traits and body composition were measured and analyzed. Levels of fat with L-carnitine had significant effects on the European Performance Efficiency Factor, wings weight, intestine length and weight, spleen and liver weight, full abdomen carcass and abdominal fat weight, as well as serum triglyceride levels. Dietary L-carnitine supplementation improved growth performance of broilers, thus it may be a promising solution to reduce fat storage in broilers and improve the quality of carcasses intended for human consumption.

Strategies to improve genomic predictions for 35 duck carcass traits in an F2 population

BackgroundCarcass traits are crucial for broiler ducks, but carcass traits can only be measured postmortem. Genomic selection (GS) is an effective approach in animal breeding to improve selection and reduce costs. However, the performance of genomic prediction in duck carcass traits remains largely unknown.ResultsIn this study, we estimated the genetic parameters, performed GS using different models and marker densities, and compared the estimation performance between GS and conventional BLUP on 35 carcass traits in an F2 population of ducks. Most of the cut weight traits and intestine length traits were estimated to be high and moderate heritabilities, respectively, while the heritabilities of percentage slaughter traits were dynamic. The reliability of genome prediction using GBLUP increased by an average of 0.06 compared to the conventional BLUP method. The Permutation studies revealed that 50K markers had achieved ideal prediction reliability, while 3K markers still achieved 90.7% predictive capability would further reduce the cost for duck carcass traits. The genomic relationship matrix normalized by our true variance method instead of the widely used sum {2p}_{i}(1-{p}_{i}) could achieve an increase in prediction reliability in most traits. We detected most of the bayesian models had a better performance, especially for BayesN. Compared to GBLUP, BayesN can further improve the predictive reliability with an average of 0.06 for duck carcass traits.ConclusionThis study demonstrates genomic selection for duck carcass traits is promising. The genomic prediction can be further improved by modifying the genomic relationship matrix using our proposed true variance method and several Bayesian models. Permutation study provides a theoretical basis for the fact that low-density arrays can be used to reduce genotype costs in duck genome selection.

Effects of dietary nisin on growth performance, slaughter traits, and thigh meat quality of quail

Abstract In this study, the growth performance, carcass yield, relative organ weight, and thigh meat quality of quail fed with diets containing different amounts of nisin as an active ingredient were investigated. A total of 400 one-day-old Japanese quail chicks were used. The quail were divided into 4 groups with five replicates and were fed with diets without (control) or with nisin (150, 300, and 500Â mg/kg). The study lasted 35 d. At the end of the experiment, a total of 80 quail, 10 males and 10 females of each group, were randomly weighed and slaughtered. After slaughtering, carcass yield, relative liver, heart, gizzard, and proventriculus weights were recorded. Stress factors (Malondialdehyde (MDA), catalase (CAT), total antioxidant status (TAS), the total of oxidant status (TOS), and oxidative stress index (OSI)) were analysed in thigh meat. Increasing levels of nisin did not affect the growth performance of quail (PÂ >Â 0.05). In terms of slaughter weight, the slaughter weight of both males and females differed among the groups (PÂ <Â 0.05). While the highest value in males was observed in the control group, the highest value in females was observed in the N150 group. Only the relative liver weights of males and the relative proventriculus weights of females were statistically different (PÂ <Â 0.01) between treatments. With increasing nisin level, the weight of the liver increased in the males and the weight of the proventriculus in the females. The addition of nisin decreased MDA and OSI values in both males and females, as compared to the control group. Furthermore, CAT and TAS values were found to be significantly higher in the nisin supplemented group than in the control group. As a result, it is concluded that adding nisin to quail feed positively affects TAS, TOS, MDA and CAT values of thigh meat and can prevent the adverse effects that may occur due to stress.

Association of ghrelin gene polymorphisms with slaughter traits in pig

Abstract It has been hypothesized that mutations in the ghrelin gene in pigs may play a similar role as in humans and may be associated with obesity. The aim of study was to analyse the polymorphisms of ghrelin gene and to evaluate its effect on pigs’ carcass traits. The effect of c.-93A&gt;G, 4428T&gt;C and g.4486C&gt;T polymorphisms at the ghrelin gene on slaughter performance was analysed in 346 gilts represented by three breeds (Polish Landrace, Duroc, Pietrain). Animals were fattened from 30 to 100 (±2.5) kg body weight. After slaughter, the carcasses were chilled for 24 hours (4ºC), weighed and the right half-carcasses were dissected and evaluated. A number of data were obtained including: meat weight in primary cuts, weight of ham, backfat thickness and carcass yield. From breeding and production point of view, the favourable results were obtained for pigs with the GG genotype at the c.-93A&gt;G locus, characterized by better carcass results than those with the AA genotype, e.g. higher ham weight and lower average backfat thickness. In pigs with the TT genotype at the g.4428T&gt;C locus, we found lower mean backfat thickness than in pigs with the CC genotype.

Effect of the dietary inclusion of Camelina sativa cake into quail diet on live performance, carcass traits, and meat quality

The present research studied the effect of the dietary inclusion of 3 different camelina (Camelina sativa (L.) Crantz) cakes on the live performance, slaughter traits, and breast meat quality of broiler quails (Coturnix japonica). With this purpose, a total of 480 fifteen-day-old broiler quails of both sexes were allocated to 48 cages (12 replicates/treatment, 10 quails/replicate) and received 4 dietary treatments: a control diet (Control), and 3 diets containing 15% of 1 commercial cultivar (Calena), and 2 improved lines (Pearl: low linoleic acid; Alan: low glucosinolates). During the experiment, individual live weight (LW) and cage feed intake were recorded to calculate body weight gain (BWG) and feed conversion ratio (FCR). At 35 d of age, quails were slaughtered, and carcasses were weighed and dissected to compute yields. On breast (pectoralis major muscle) the measurements and analyses considered ultimate pH, L*a*b* color values, proximate composition, oxidative status, cooking loss and WBSF toughness. Broiler quails receiving diets with camelina cakes exhibited mortality and health status similar to the control. However, growth performance was impaired in camelina-fed groups, especially for Calena (P < 0.05). Overall LW and BWG were slightly lower, whereas feed intake was slightly higher in camelina-fed groups compared to Control (P > 0.05). Therefore, higher FCR was recorded for camelina-fed groups compared to Control (P=0.0004). Moreover, breast meat from Calena treatment displayed higher water (P=0.0170), and lower lipid (P=0.0051) contents compared to those of the Control group, while protein and ash content remained unaffected. Heme-iron content and oxidative status of breast meat were not influenced by the dietary incorporation of camelina (P > 0.05). The research outcomes indicated that camelina cakes can be used as an alternative feed ingredient for broiler quails' diets, without compromising carcass yields and meat quality. However, as 15% dietary incorporation worsened live performance, the ideal camelina cake inclusion level should be thoroughly investigated as well as a parallel research effort into further reducing glucosinolates content of camelina.

An analytical framework to predict slaughter traits from images in fish

An analytical framework to predict slaughter traits from images in fish

Efficiency of leptin gene polymorphisms in the evaluation of the growth performance and carcass measurements of v-line and Baladi black rabbits

This study investigated the association between both polymorphisms and metabolic marker changes of the leptin gene, and body weight, weight gain, carcass traits, feed intake, and feed conversion ratio. Blood samples were collected from 60 V-line and 60 Baladi Black rabbits for DNA extraction and biochemical analysis. DNA sequencing of leptin (202-bp) revealed four non-synonymous single nucleotide polymorphism (SNPs) that characterized a number of V-line rabbits. Statistical analysis revealed that the identified SNPs were associated with rabbit growth and carcass measurements (p &lt; 0.05). A discriminant analysis model showed a high classification percentage for the identified SNPs within and between breeds using body weight at 5-14 weeks of age (91.7%), slaughter traits (91.6%), feed intake, daily feed intake, and feed conversion ratio (76.7%). This study reveals that leptin gene could be a candidate for growth traits in rabbits enabling the development of marker-assisted selection (MAS) in different rabbit breeds.

Carcass and meat quality traits of IPB D1 chicken on black soldier fly larvae (BSFL) dietary inclusion

The aims research studied the effect of the dietary inclusion of 3 different levels of black soldier fly larvae (BSFL) meal on the slaughter traits and meat nutritional quality of IPB D1 chicken (composite chicken: Pelung, Sentul, Kampung, Cobb Broiler). Five hundred and fifteen IPB D1 chickens were randomly allocated into three treatment groups (P0, P1, and P2) with three replicates/treatment, fifty-five to sixty chickens /replicate). The treatment groups consist of control feed ration (without BSFL)/ T0), 5% BSFL (T1), and 7.5% BSFL (T2). At 8, 9, and 10 weeks of age, eighteen IPB D1 chickens were slaughtered and separated between male and female, afterward, carcasses were weighed and parted into commercial parts. Proximate and Cholesterol analysis conducted on the breast, tight, and leg meat. The research outcomes indicated that BSFL meal as feedstuff showed similar carcass yield at each 8, 9, and 10 weeks of age in male and female chickens. IPB D1 chicken meat from BSFL (T1 and T2) treatment had higher fat content than control both in males and female chicken at 10-week ages. The protein percentage showed insignificant in all treatments, with a range from 19.85%-22.89% in male meat, and 21%-21.62% in female meat.

Effects of Heat Stress on Growth Performance, Carcass Traits, Physiological Components, and Biochemical Parameters in Local Algerian Growing Rabbits

Heat stress is a detrimental factor affecting the welfare of all livestock, especially rabbits, as they are sensitive to high temperatures. The current study investigated the effect of high ambient temperature on growth performance, slaughter traits, physiological indicators, and some hematological and biochemical parameters in Algerian local growing rabbits. A total of 48 local rabbits of both sexes (35 days old) were allotted into two groups (24 per group). The control group rabbits were exposed to an ambient temperature and humidity, averaging 21.8 ± 1.3°C and 51.7 ± 3.6%, respectively. Rabbits in the heat stress group were subjected to a warm ambient temperature and humidity of 30.5 ± 1.82°C and 65.5 ± 7.2%, respectively. The growth performance was measured and calculated from 35 to 91 days of age. Physiological indicators (rectal, skin, and ear temperatures, respiratory, and heart rates) were examined at 88 days of age. The carcass traits, blood metabolites, and hematological parameters of rabbits were measured and calculated at slaughter (92 days of age). The obtained results indicated a decrease in body weight, daily gain, and daily feed intake of rabbits in heat stress rabbits, compared to the control group. However, feed conversion ratio was significantly higher in the heat stress group, compared to the control. Heat stress group rabbits showed significantly higher blood metabolite levels, except the glycemia, which was similar in both groups. No significant effect of heat stress was found on the carcass yield, anterior, posterior, and intermediate parts of the carcass. However, the yield of the other components of the carcass (liver, kidney, peritoneal and inter-scapular fat) was significantly lower in the heat stress group. In the heat stress group, rectal, skin, and ear temperatures as well as heart and respiratory rates, were significantly higher than those of the control group. In the present experimental conditions, exposure of local rabbits to chronic heat stress could induce some changes to biological, physiological, and biochemical parameters leading to altered growth performance.

Manifestation of living and post-slaughter traits of productivity in inbred and outbred bull calves of Ukrainian meat cattle breed

Selection in meat cattle herds requires caution due to the manifestation of inbred depression in traits that affect the economics of this livestock industry. This paper analyses the productivity of inbred and outbred bull calves of the Ukrainian meat cattle breed and justifies methods of pair selection in purebred herds with natural pairing. In bull calves, the growth of animals and traits of their meat productivity after slaughter were considered. Inbreeding was determined based on their pedigree. Inbred animals tended to have a growth rate of 10.2% from birth to 8 months of age. Afterwards, their average daily gain in live weight decreases sharply compared to outbred peers, who grow faster over a more extended period. From 8 to 18 months of age, it is probably (p &gt;0.95) higher by 27.3% compared to inbred animals. Inbred bull calves have higher variability (Cv,%) in average daily gains. This indicates different adaptations to the environment during the suckling period and after weaning. Outbred animals tend to gain 2.3% of body weight at 12 months, 4.7 at 15 months, and 10.3% at 18 months. Its variability with age decreases by 7.4 points in inbred bull calves and 0.4 points in outbred ones, from 8 to 18 months. The inbred animals spent 29.5% more feed per kg of gain (p &gt;0.95) than the outbred ones. Inbred bull calves vs outbred ones at 15 and 18 months of age tend to improve the expression of meat forms by 1.3 and 2.7%. They are relatively shorter and have a more rounded barrel. As a result, they have a shorter period of rapid growth. With the small size of the Ukrainian meat cattle population, one of the most important problems is reducing genetic variation in beef productivity traits and manifesting inbred depression in them. In purebred commercial herds, the mating of close animals should be avoided. To do this, an "order" for bulls should be made, and pairs should be selected without using inbreeding at different grades. Thus, outbred bull calves will reach live weight more quickly, spending less feed per growth unit, and have better basic slaughter traits.

Factors Affecting Breast Myopathies in Broiler Chickens and Quality of Defective Meat: A Meta-Analysis.

Fast-growing broiler chickens are subjected to breast myopathies such as white striping (WS), wooden breast (WB), and spaghetti meat (SM). Available studies about risk factors for myopathy occurrence often used flock data whereas a few reports evaluated chicken individual data. Thus, the present study aimed to elucidate the effect of growth and slaughter traits, besides sex and genotype on myopathy occurrence. Data were obtained from eight experimental trials, which used a total of 6,036 broiler chickens. Sex, genotype, daily weight gain, slaughter weight, and breast yield were evaluated as potential risk factors by logistic regression analyses. Then, the effects of myopathy and sex were evaluated on meat rheological traits (pH, colour, cooking losses and shear force). Based on a logistic regression, WS occurrence was associated with genotype, breast weight, and breast yield. Compared with chickens with intermediate breast weight and breast yield, higher odds of having WS were found in chickens with high breast weight (OR: 1.49) and yield (OR: 1.27), whereas lower odds were found in those with low breast weight (OR: 0.57) and yield (OR: 0.82). As for WB and SM, females had lower odds of having WB (OR: 0.55) and higher odds of showing SM (OR: 15.4) compared to males. In males, higher odds of having WB were found in chickens with a high daily weight gain (OR: 1.75) compared to those with an intermediate daily weight gain. In females, higher odds of having SM were associated to a high slaughter weight (OR: 2.10) while lower odds to a low slaughter weight (OR: 0.87). As for meat quality, only WB meat was clearly different for some technological and sensorial properties, which can play a major role also in meat processing. In conclusion, our analysis identified breast development as a potential risk factor for WS, while a high growth was the risk factor for WB and SM. A different probability of having WB or SM in females and male was found.

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.

Sun-dried Stylo Hay (Stylosanthes guianensis CIAT 184) as Dietary Fibre Source in Rabbits

Background: In West Africa, one of the main problem of rabbit production is the lack of fibre-balanced feeds available at remunerative price, as the supply of fibrous raw material remains difficult. Expensive fibrous raw materials imported from temperate countries are the most fibre source used in rabbit feed formulation. This study aimed to assess the nutritive value and the potential use of Stylosanthes guianensis CIAT 184, a local fodder, as dietary fibre source in rabbit feed. Methods: Four diets containing an inclusion of Stylo hay: 0% (control, SH0), 15% (SH15), 30% (SH30) and 45% (SH45) as a substitute for the control diet (33.3 g NDF and 170 g CP/kg) were studied. Four groups of 12 rabbits, individually caged, were fed ad libitum the 4 diets, from weaning (35 days) to 78 days age. Result: Replacing up to 45% the basal diet with Stylo hay reduced nutrients digestibility (P less than 0.001). The digestible protein (DP) contain of Stylo hay was 36±0.57 g/kg DM. The inclusion of Stylo up to 30% in the diet improved animals growth rate compared to the control diet. Health status and slaughter traits were not affected by Stylo incorporation. It was concluded that sun-dried Stylo hay could be considered as a good fibre source in the complete pellet feed for rabbits in West Africa.

Genetic parameter estimates of chick quality, growth, and carcass characteristics in Japanese quail

The aim of this study was to estimate the heritabilities of chick quality and growth traits and their genetic relationships with some slaughter traits. Chick quality was determined using both Tona and Pasgar score methods. All birds were slaughtered at 8 weeks of age to measure carcass yield (CY), and percentage of breast (BY), leg (LY), wing (WY), abdominal fat (AFY). Heritability estimates for chick quality scores of Tona and Pasgar were found 0.08, and 0.09, respectively. Heritability estimates for growth curve parameters and inflection point coordinates of the Gompertz model were low to moderate, with values ranging from 0.17 to 0.26. Low heritability estimates for CY, BY, LY, and WY were found 0.04, 0.14, 0.09, and 0.07, respectively. Genetic and phenotypic correlations between chick quality and BW-growth traits were determined low and statistically non-significant (P&gt;0.05). Similarly, genetic and phenotypic relationships between chick quality and carcass yield, and between chick quality and percentages of carcass parts were found low and statistically non-significant (P&gt;0.05). As a result, it is possible to say that applying multitrait selection, including chick quality, will not affect other yield characteristics positively or negatively. However, in virtue of the chick quality is a very low heritable trait, environmental improvement of chick quality trait may be considered rather than genetic improvement.

ВЛИЯНИЕ НА БИЛКОВИ И ИМУНОМОДУЛИРАЩИ ДОБАВКИ ВЪРХУ РАСТЕЖНИТЕ СПОСОБНОСТИ И КАЧЕСТВОТО НА МЕСОТО ПРИ ПИЛЕТА БРОЙЛЕРИ

This study aimed to evaluate the effect of herbal and immunomodulatory die-tary supplements and their combinations on growth performance, slaughter traits and meat quality in male broiler chickens. A total of 210 one-day-old Ross 308 male chickens were randomly distributed after weighing in 7 groups (3 replicates in each, n=10 chickens). Broilers were reared on deep litter until 42 days of age and divided as follows: Group I – control (basal diet without supplements); Group II – supple-mented with 0.2% Immunoßeta; Group III – supplemented with 0.2% garlic powder; Group IV – supplemented with 0.2% herbal mix (0.05% ginger, 0.05% rosemary, 0.05% thyme and 0.05% yarrow); Group V – supplemented with 0.2% Immunoßeta + 0.2% garlic powder; Group VI – supplemented with 0.2% Immunoßeta + 0.2% herbal mix; Group VII – supplemented with 0.2% Immunoßeta + 0.2% garlic powder + 0.2% herbal mix. At the end of the experiment, chickens weighed from 2552±54 g (Group I) to 2689±55 g (Group IV) without statistically significant differences (Р>0.05). Feed conversion varied from 1.64 (Group IV) tо 1.74 (Group I). Meat pH, water holding ca-pacity, water absorption capacity, and tenderness were not influenced by the dietary supplement type. All supplements used did not show an adverse effect on health, and no mortality was found in the experimental groups. The obtained results show a clear trend towards a positive effect of the used feed additives and their combination mainly on the fattening characteristics of the broiler chickens, evident from the higher values of the two efficiency indices.