Blood Traits Research Articles

The effect of adding two types of organic chromium to the diet of common carp Cyprinus carpio L. on some blood and biochemical traits.

This research was carried out in the fish laboratory of the Department of Animal Production/College of Agriculture and Forestry/University of Mosul. 147 common carp, Cyprinus carpio L., were used with an average initial weight of 27.60 ± 2 gm/fish, distributed over seven experimental treatments, with three replicates for each treatment. The fish were acclimatized before the experiment for twenty-one days to the aquarium environment and food intake. Two types of organic chromium were added, namely chromium picolinate, at an amount of 0.3, 0.4, and 0.5 mg/kg feed (T2, T3, and T4), and 0.3, 0.4, and 0.5 mg/kg feed of chromium nicotinate (T5, T6, and T7), besides the control diet without additives (T1), which was balanced in terms of crude protein and metabolic energy. Results of the statistical analysis showed that the fish fed the experimental diets T3 and T7 were significantly superior (P? 0.05) in terms of hemoglobin and PCV to the rest of the experimental diets, including the control diet. Fish fed the T6 diet recorded a significant superiority over the rest of the other experimental treatments in the total blood protein and globulin standards, while no significant differences were observed between the different experimental treatments with the exception of the control diet, which was significantly behind the rest of the treatments in the albumin standard. Fish fed the control diet outperformed the parameters of blood sugar, triglycerides, AST, and ALT significantly more than the rest of the experimental treatments. It turns out that adding both types of organic chromium (organic chromium picolinate and nicotinate) at a rate of 0.5 mg/kg feed gave the best results in most of the criteria studied.

Blood parameters predicted from milk spectra are candidate indicator traits of hyperketonemia - a retrospective study in the Italian Holstein population.

At the onset of lactation, high-producing dairy cows commonly face a negative energy balance and consequent metabolic disorders, such as hyperketonemia. Blood concentrations of nonesterified fatty acids (NEFA), BHB, cholesterol, glucose and urea provide valuable information about the metabolic, health, and nutritional status of lactating animals. Milk mid-infrared (MIR) spectroscopy has been successfully used for the prediction of several health traits, including concentration of blood metabolites even though the models' accuracy is moderate. In fact, MIR-predicted blood parameters are useful for population screening and may be used for selective breeding if they are heritable and genetically variable within a population. In the present study we estimated h2 and genetic correlation of MIR-predicted BHB, NEFA, glucose, cholesterol and urea and assessed their genetic correlation with milk yield and composition traits in the Italian Holstein population using phenotypes of 9,943 cows in 460 herds. Two sets were considered: early (8,277 records - 1 per cow - between 5 and 35 d in milk) and whole lactation (105,293 records - at least 5 per cow - between 5 and 305 d in milk). The h2 and genetic variability of blood traits were greater in early than whole lactation, confirming that there is room to manipulate metabolic disease incidence in the transition period through selection. Blood BHB was the most heritable trait, no matter the lactation stage (0.13 and 0.08 in early and whole lactation), while NEFA was the least heritable trait, with h2 not significantly different from zero. Blood BHB was positively genetically correlated with NEFA, whereas glucose was negatively correlated with BHB, NEFA and urea. Blood BHB, NEFA and cholesterol were generally positively correlated with milk fat-to-protein ratio; BHB was negatively correlated with lactose content and positively with SCS. Estimated breeding values of sires with at least 20 daughters with phenotypes available were extrapolated for a-posteriori evaluation of the observed performance. The progeny of the top 5 sires exhibited a lower incidence of hyperketonemia compared with the other cows, with only 2.16% of cows having BHB concentration above the conventional threshold (1.2 mmol/L). Conversely, the prevalence of hyperketonemia was 5 times higher in the offspring of the bottom 5 bulls (10.55% cows with BHB >1.2 mmol/L). These findings suggest that, despite of the low h2 estimates, there is room to identify animals with low or high genetic merit for traits linked to the cow's metabolism. Therefore, the selection toward healthier and metabolically resistant cows is pursuable, with the infrared-predicted blood traits being potential auxiliary traits.

Impact of Varying Dosages of Powdered Melissa Officinalis Leaf on Certain Blood and Microbiological Traits in Broiler Intestines

The study used 180 unsexed one-day-old Ross-308 broiler chicks. After that, the chicks were divided into four treatments at random, with three replicates of each treatment (15 chicks per replicate). The initial treatment, T1 (comparison), was an additive-free control diet. For one to four days, the powdered Melissa leaves were added to the second treatment (T2), third treatment (T3), and fourth treatment (T4) at the following concentrations: 0, 4, 6, and 8 g/kg feed, respectively. The findings showed that, as compared to the control treatment, adding Melissa leaf powder significantly (P<0.05) reduced the levels of low-density lipoproteins, triglycerides, cholesterol, and glucose. Additionally, the results showed that the addition treatments significantly increased the number of red blood cells, packed blood cell volume, and hemoglobin in the blood of the birds. It was also observed that the addition of Melissa leaf powder had a positive effect on intestinal bacteria, reducing the number of colon and total bacteria and significantly improving the number of lactobacilli. Based on this, we conclude that broiler chickens' blood and microbial characteristics significantly improved when they were fed crushed Melissa leaf powder. The concentration of 8 g/kg feed produced the best results when compared to the other concentrations and for all aspects of the study.

Phenotypic variation of dairy cows' hematic metabolites and feasibility of non-invasive monitoring of the metabolic status in the transition period.

The incidence of metabolic diseases tends to be highest during the transition period (±3 weeks around parturition) in dairy cows due to physiological changes and the onset of lactation. Although blood profile testing allows for the monitoring of nutritional and metabolic status, conducting extensive analyses in the herd is costly and stressful for cows due to invasive procedures. Therefore, mid-infrared spectroscopy (MIR) could be seen as a valid alternative. In the present study, we used laboratory-determined reference blood data and milk spectra of 349 Holstein cows to (i) identify the non-genetic factors affecting the variability of major blood traits in healthy cows and, subsequently, (ii) test the predictive ability of milk MIR. Cows belonged to 14 Italian commercial farms and were sampled once between 5 and 38 days in milk. For β-hydroxybutyrate (BHB), non-esterified fatty acids (NEFA), cholesterol, glucose, urea, total protein, albumin, globulin, minerals, aspartate aminotransferase, gamma-glutamyl transferase, creatine kinase, total bilirubin, and cortisol, the effects of parity, days in milk, and season were investigated using a linear model. The results indicate that all fixed effects significantly affected the hematic concentration of most of the traits. Regarding MIR, the most predictable traits were BHB, NEFA, and urea, with coefficients of determination equal to 0.57, 0.62, and 0.89, respectively. These values suggest that MIR predictions of BHB and NEFA are not sufficiently accurate for precise and punctual determination of the hematic concentration, however, still the spectrum of the milk can be exploited to identify cows at risk of negative energy balance and subclinical ketosis. Finally, the predictions can be useful for herd screening, decision-making, and genetic evaluation.

Prospective study on the association between 36 human blood cell traits and pan-cancer outcomes: a mendelian randomization analysis

BackgroundResearch on the link between blood cell traits and cancer risk has gained significant attention. Traditional epidemiological and cell biology studies, have identified correlations between blood traits and cancer risks. These findings are important as they suggest potential risk factors and biological mechanisms. However, these studies often can’t confirm causality, pointing to the need for further investigation to understand these relationships better.MethodsMendelian randomization (MR), utilizing single-nucleotide polymorphisms as instrumental variables, was employed to investigate blood cell trait causal effects on cancer risk. Thirty-six blood cell traits were analyzed, and their impact on 28 major cancer outcomes was assessed using data from the FinnGen cohort, with eight major cancer outcomes and 22 cancer subsets. Furthermore, 1,008 MR analyses were conducted, incorporating sensitivity analyses (weighted median, MR-Egger, and MR-PRESSO) to address potential pleiotropy and heterogeneity.ResultsThe analysis (data from 173,480 individuals primarily of European descent) revealed significant results. An increase in eosinophil count was associated with a reduced risk of colorectal malignancies (OR = 0.7702 per 1 SD higher level, 95% CI = 0.6852 to 0.8658; P = 1.22E-05). Similarly, an increase in total eosinophil and basophil count was linked to a decreased risk of colorectal malignancies (OR = 0.7798 per 1 SD higher level, 95% CI = 0.6904 to 0.8808; P = 6.30E-05). Elevated hematocrit (HCT) levels were associated with a reduced risk of ovarian cancer (OR = 0.5857 per 1 SD higher level, 95% CI = 0.4443 to 0.7721; P = 1.47E-04). No significant heterogeneity or horizontal pleiotropy was observed.ConclusionsOur study highlights the complex and context-dependent roles of blood cell traits in cancers.

Potential Predictive Value of Platelet Distribution Width for Functional Outcome After Ischemic Stroke.

Complete blood cell count (CBC) is the most common and readily available laboratory test in clinical practice. The relationships of some CBC indices with ischemic stroke have been reported in observational studies; however, the causal direction is not specified. This study aimed to explore the causal relationships between CBC indices and the modified Rankin Scale (mRS) score at 3months after ischemic stroke. Genetic associations of 22 blood cell traits were obtained from the UK Biobank database (n = 350,475). The outcome data for ischemic stroke were obtained from the Genetic Ischemic Stroke Functional Outcome (GISCOME) network (n = 6021). We implemented two-sample Mendelian randomization (TSMR) and several complementary analyses to assess the causal association between blood traits and unfavorable outcome (3-month mRS > 2). The clinical cohort was validated based on the results of the MR analysis. TSMR result indicated causal association between genetically determined platelet distribution width (PDW) and adverse functional outcome after ischemic stroke (OR 1.48; 95% CI 1.13-1.95; p = 0.005). Complementary analyses showed negligible causal effect of genetic variants on stroke subtypes. In cohort study (n = 351), higher level of PDW was observed in the unfavorable outcome group. However, the multivariable logistic regression analysis failed to identify the improvement in predictive performance of stroke outcomes by adding PDW to the prediction model. Further correlation analysis revealed that PDW is positively correlated with serum glucose levels, and the level of PDW in the non-thrombolysed group was significantly higher than that in the thrombolysis group, indicating that PDW may be involved in stroke prognosis in an indirect way.

Genome-wide association study reveals the underlying regulatory mechanisms of red blood traits in Anadara granosa

BackgroundAnadara granosa, commonly known as the blood clam, exhibits the unusual characteristic of having red blood among invertebrates. There is significant individual variation in blood color intensity among blood clams; individuals with vibrant red blood are deemed healthier and exhibit stronger stress resistance. However, the molecular basis underlying these red blood traits (RBTs) remains poorly understood.ResultsIn this study, we performed genome-wide association studies (GWAS) in a population of 300 A. granosa individuals, focusing on RBTs as measured by hemoglobin concentration (HC), total hemocyte count (THC), and heme concentration (HEME). Our analysis identified 18 single nucleotide polymorphisms (SNPs) correlated with RBTs, subsequently selected 117 candidate genes within a 100 kb flanking region of these SNPs, potentially involved in the RBTs of A. granosa. Moreover, we discovered two haplotype blocks specifically associated with THC and HEME. Further analysis revealed eight genes (Septin7, Hox5, Cbfa2t3, Avpr1b, Hhex, Eif2ak3, Glrk, and Rpl35a) that significantly influence RBTs. Notably, a heterozygous A/T mutation in the 3’UTR of Cbfa2t3 was found to promote blood cell proliferation. These genes suggest that the hematopoietic function plays a significant role in the variability of RBTs in A. granosa.ConclusionsOur findings reveal a conservation of the regulatory mechanisms of RBTs between blood clams and vertebrates. The results not only provide a scientific basis for selective breeding in blood clams, but also offer deeper insights into the evolutionary mechanisms of RBTs in invertebrates.

Variance quantitative trait loci reveal gene-gene interactions which alter blood traits.

Gene-gene (GxG) interactions play an important role in human genetics, potentially explaining part of the "missing heritability" of polygenic traits and the variable expressivity of monogenic traits. Many GxG interactions have been identified in model organisms through experimental breeding studies, but they have been difficult to identify in human populations. To address this challenge, we applied two complementary variance QTL (vQTL)-based approaches to identify GxG interactions that contribute to human blood traits and blood-related disease risk. First, we used the previously validated genome-wide scale test for each trait in ∼450,000 people in the UK Biobank and identified 4 vQTLs. Genome-wide GxG interaction testing of these vQTLs enabled discovery of novel interactions between (1) CCL24 and CCL26 for eosinophil count and plasma CCL24 and CCL26 protein levels and (2) HLA-DQA1 and HLA-DQB1 for lymphocyte count and risk of celiac disease, both of which replicated in ∼140,000 NIH All of Us and ∼70,000 Vanderbilt BioVU participants. Second, we used a biologically informed approach to search for vQTL in disease-relevant genes. This approach identified (1) a known interaction for hemoglobin between two pathogenic variants in HFE which cause hereditary hemochromatosis and alters risk of cirrhosis and (2) a novel interaction between the JAK2 46/1 haplotype and a variant on chromosome 14 which modifies platelet count, JAK2 V617F clonal hematopoiesis, and risk of polycythemia vera. This work identifies novel disease-relevant GxG interactions and demonstrates the utility of vQTL-based approaches in identifying GxG interactions relevant to human health at scale.

Sequence variants influencing the regulation of serum IgG subclass levels

Immunoglobulin G (IgG) is the main isotype of antibody in human blood. IgG consists of four subclasses (IgG1 to IgG4), encoded by separate constant region genes within the Ig heavy chain locus (IGH). Here, we report a genome-wide association study on blood IgG subclass levels. Across 4334 adults and 4571 individuals under 18 years, we discover ten new and identify four known variants at five loci influencing IgG subclass levels. These variants also affect the risk of asthma, autoimmune diseases, and blood traits. Seven variants map to the IGH locus, three to the Fcγ receptor (FCGR) locus, and two to the human leukocyte antigen (HLA) region, affecting the levels of all IgG subclasses. The most significant associations are observed between the G1m (f), G2m(n) and G3m(b*) allotypes, and IgG1, IgG2 and IgG3, respectively. Additionally, we describe selective associations with IgG4 at 16p11.2 (ITGAX) and 17q21.1 (IKZF3, ZPBP2, GSDMB, ORMDL3). Interestingly, the latter coincides with a highly pleiotropic signal where the allele associated with lower IgG4 levels protects against childhood asthma but predisposes to inflammatory bowel disease. Our results provide insight into the regulation of antibody-mediated immunity that can potentially be useful in the development of antibody based therapeutics.

The Effect of Adding Azolla Plant Powder in Quail Diets on The Carcass Traits and Some Blood Traits

The Effect of Adding Azolla Plant Powder in Quail Diets on The Carcass Traits and Some Blood Traits

Tropomyosin 1 deficiency facilitates cell state transitions and enhances hemogenic endothelial cell specification during hematopoiesis

Tropomyosins coat actin filaments to impact actin-related signaling and cell morphogenesis. Genome-wide association studies have linked Tropomyosin 1 (TPM1) with human blood trait variation. TPM1 has been shown to regulate blood cell formation invitro, but it remains unclear how or when TPM1 affects hematopoiesis. Using gene-edited induced pluripotent stem cell (iPSC) model systems, we found that TPM1 knockout augmented developmental cell state transitions and key signaling pathways, including tumor necrosis factor alpha (TNF-α) signaling, to promote hemogenic endothelial (HE) cell specification and hematopoietic progenitor cell (HPC) production. Single-cell analyses revealed decreased TPM1 expression during human HE specification, suggesting that TPM1 regulated invivo hematopoiesis via similar mechanisms. Analyses of a TPM1 gene trap mouse model showed that TPM1 deficiency enhanced HE formation during embryogenesis, without increasing the number of hematopoietic stem cells. These findings illuminate novel effects of TPM1 on developmental hematopoiesis.

PRCP is a promising drug target for intracranial aneurysm rupture supported via multi-omics analysis

BackgroundCerebral aneurysms are life-threatening cerebrovascular disorders. Currently, there are no effective treatments for preventing disease progression. Mendelian randomisation (MR) is widely used to repurify licensed drugs and identify new therapeutic...

RELATIONSHIP BETWEEN SERUM ALKALINE PHOSPHATASE AND MEAT QUALITY TRAITS IN MALE AND FEMALE BROILER LINES IN SHIKA, NIGERIA

This study was conducted to genetically evaluate the relationship between serum alkaline phosphatase (SAP) and meat quality traits of male and female broiler lines in National Animal Production Research Institute (NAPRI). A total of 350 broiler birds were used, which consisted of 100 birds each for sire and dam line and 75 birds each for sire control and dam control. Data on blood and meat quality traits were analyzed using General Linear Model procedures of SAS (2002). The results obtained indicated that there was no significant (P>0.05) difference in all the biochemical traits observed except in the SAP where sire control showed the highest value of 69.00mg/dl. No significant (P>0.05) differences were observed in meat quality traits except in the energy value of sire control (3945.3kcal/kg). Genetic correlations obtained in this study revealed that SAP showed positive and negative correlations with meat quality traits for the selected lines. It was therefore concluded that, lines had significant effects on SAP and energy. High genetic correlations between SAP and meat quality traits are indications of linkage and pleiotropy effects among these traits.

Causal relationship between blood traits and severe influenza A(H1N1)pdm09 infection in East Asian: A Mendelian randomization study.

Although a range of blood traits have been reported to be associated with influenza A(H1N1)pdm09 (H1N1pdm09) disease severity, their underlying causal relationships and biological mechanisms have remained unclear. This study aimed to investigate the causal relationship between blood traits and H1N1pdm09 using a two-sample Mendelian randomization analysis. Based on the data from our in-house genome-wide association study (GWAS) on H1N1pdm09 disease severity (Ncase [severe] = 70, Ncontrol [mild] = 95) and GWAS summaries of 44 blood traits from Biobank Japan (N = 12 303-143 658), we identified the potential causal effect of blood traits on severe H1N1pdm09. The inversevariance weightedmethodanalysis revealed significant causal effects of lower aspartate aminotransferase (AST, β = -3.212, p = 0.019), low-density-lipoprotein cholesterol (LDL-C, β = -1.372, p = 0.045), and basophil counts (Baso, β = -1.638, p = 0.047) on severe H1N1pdm09 disease. Additionally, polygenic risk score analysis further confirmed genetic overlap between these blood traits and severe H1N1pdm09 disease. This study provided evidence linking the lower level of AST, LDL-C, and lower count of Baso with severe H1N1pdm09 disease, potentially identifying new therapeutic targets for patients with severe influenza.

The broad impact of cell death genes on the human disease phenome

Cell death mediated by genetically defined signaling pathways influences the health and dynamics of all tissues, however the tissue specificity of cell death pathways and the relationships between these pathways and human disease are not well understood. We analyzed the expression profiles of an array of 44 cell death genes involved in apoptosis, necroptosis, and pyroptosis cell death pathways across 49 human tissues from GTEx, to elucidate the landscape of cell death gene expression across human tissues, and the relationship between tissue-specific genetically determined expression and the human phenome. We uncovered unique cell death gene expression profiles across tissue types, suggesting there are physiologically distinct cell death programs in different tissues. Using summary statistics-based transcriptome wide association studies (TWAS) on human traits in the UK Biobank (n ~ 500,000), we evaluated 513 traits encompassing ICD-10 defined diagnoses and laboratory-derived traits. Our analysis revealed hundreds of significant (FDR < 0.05) associations between genetically regulated cell death gene expression and an array of human phenotypes encompassing both clinical diagnoses and hematologic parameters, which were independently validated in another large-scale DNA biobank (BioVU) at Vanderbilt University Medical Center (n = 94,474) with matching phenotypes. Cell death genes were highly enriched for significant associations with blood traits versus non-cell-death genes, with apoptosis-associated genes enriched for leukocyte and platelet traits. Our findings are also concordant with independently published studies (e.g. associations between BCL2L11/BIM expression and platelet & lymphocyte counts). Overall, these results suggest that cell death genes play distinct roles in their contribution to human phenotypes, and that cell death genes influence a diverse array of human traits.

The The Effect of Adding Different Levels of Aqueous Extract of Cloves to the Drinking Water of Broiler Chickens (Ross 308) on Blood Biochemical Characteristics and Some Indicators of Oxidative Stress

This study was conducted in the poultry field of the Department of Animal Production College of Agriculture - University of Karbala for a period of 35 days, from 6/10/2022 to 9/11/2022, to demonstrate the effect of the aqueous extract of cloves added to the drinking water of broiler chickens on blood traits. Biochemistry and some indicators of oxidation, where 240 Ross308 broiler chicks were used, one day old, unsexed, and the average weight of the chicks was 40 gm, distributed randomly into 4 treatments and each treatment 3 replicates of 20 chicks "for each replicate, and the aqueous extract was added to the drinking water Since the first day, my agencies: T1: control treatment without addition, T2: adding 10 ml / liter of water, T3: adding 20 ml / liter of water, T4: adding 30 ml / liter of water, and the most important results that we obtained were summarized: A highly significant increase (p≤ 01) in the blood serum glucose concentration of the T4 treatment compared to the control treatment. As for the T3 treatment, it excelled at the level of (p≤ 0.01) in the concentration of total protein, albumin and globulin, as well as cholesterol, triglycerides and LDL, compared to the control treatment. The results showed a highly significant increase (p ≤ 0.01) in the ALT enzyme for the T3 treatment. As for the AST enzyme, its concentration increased in the T2 treatment, which was similar to the control treatment in the significance of this enzyme. In the same results, a highly significant (p ≤ 0.01) superiority was observed in the concentration of GPX enzyme for T4, T3 treatment over T2, T1 treatments. As for the CAT enzyme, its concentration increased at a significant level (p ≤ 0.01) in T3 treatment birds, but it was significantly similar to the control treatment. As for the T4 treatment, it increased significantly in the MDA rate compared to the control treatment

Searching for gene-gene interactions through variance quantitative trait loci of 29 continuous Taiwan Biobank phenotypes.

Introduction: After the era of genome-wide association studies (GWAS), thousands of genetic variants have been identified to exhibit main effects on human phenotypes. The next critical issue would be to explore the interplay between genes, the so-called "gene-gene interactions" (GxG) or epistasis. An exhaustive search for all single-nucleotide polymorphism (SNP) pairs is not recommended because this will induce a harsh penalty of multiple testing. Limiting the search of epistasis on SNPs reported by previous GWAS may miss essential interactions between SNPs without significant marginal effects. Moreover, most methods are computationally intensive and can be challenging to implement genome-wide. Methods: I here searched for GxG through variance quantitative trait loci (vQTLs) of 29 continuous Taiwan Biobank (TWB) phenotypes. A discovery cohort of 86,536 and a replication cohort of 25,460 TWB individuals were analyzed, respectively. Results: A total of 18 nearly independent vQTLs with linkage disequilibrium measure r 2 < 0.01 were identified and replicated from nine phenotypes. 15 significant GxG were found with p-values <1.1E-5 (in the discovery cohort) and false discovery rates <2% (in the replication cohort). Among these 15 GxG, 11 were detected for blood traits including red blood cells, hemoglobin, and hematocrit; 2 for total bilirubin; 1 for fasting glucose; and 1 for total cholesterol (TCHO). All GxG were observed for gene pairs on the same chromosome, except for the APOA5 (chromosome 11)-TOMM40 (chromosome 19) interaction for TCHO. Discussion: This study provided a computationally feasible way to search for GxG genome-wide and applied this approach to 29 phenotypes.

The impact of using slow-release urea instead of fast-release urea in feed on the milk production of Awassi sheep and some blood traits

The impact of using slow-release urea instead of fast-release urea in feed on the milk production of Awassi sheep and some blood traits

Genetic estimates studies of morphometric, physiological and blood traits of mixed breed of rabbits

This study was conducted to determine the genetic estimates and blood traits of mixed breed of rabbits at different stages of growth. Three hundred and sixty rabbits comprising crosses of New Zealand White and Chinchilla breeds were used. Morphometric traits such as body weight, shoulder to tail length, head to shoulder length, trunk length, height at withers, ear length, heart girth, forelimb length, hind limb length and nose to shoulder length were recorded weekly. Blood samples were taken at 32 and 48 weeks to assess haematological and serum biochemical indices while physiological parameters such as rectal temperature, pulse rate and respiratory rate were determined as well. The data collected were analyzed using SAS (2008) to determine the phenotypic correlations among blood and physiological traits of mixed breed of rabbits; to estimate realized heritability and repeatability of morphometric and physiological traits. Results obtained are low to high heritability (0.13 to 0.99) and repeatability (0.07 to 0.90) estimates of morphometric and physiological parameters from mixed breeds of rabbits at different ages were obtained in this study. The high heritability estimates could be as a result of additive gene effect that gave rise to high genetic variability. The implication of this is that individual selection will lead to high genetic gain, while the repeatability of these traits being high, suggests that the likelihood to repeat these records is high. Further studies should be conducted involving larger datasets, which would yield more precise estimates of heritability and repeatability Cette étude a été menée pour déterminer les estimations génétiques et les traits sanguins de races mixtes de lapins à différents stades de croissance. Trois cent soixante lapins issus de croisements de races néo-zélandaises blanches et chinchillas ont été utilisés. Les caractéristiques morphométriques telles que le poids corporel, la longueur de l'épaule à la queue, la longueur de la tête à l'épaule, la longueur du tronc, la hauteur au garrot, la longueur des oreilles, la circonférence du cœur, la longueur des membres antérieurs, la longueur des membres postérieurs et la longueur du nez à l'épaule ont été enregistrées chaque semaine. Des échantillons de sang ont été prélevés à 32 et 48 semaines pour évaluer les indices hématologiques et biochimiques sériques, tandis que les paramètres physiologiques tels que la température rectale, le pouls et la fréquence respiratoire ont également été déterminés. Les données collectées ont été analysées à l'aide de SAS (2008) pour déterminer les corrélations phénotypiques entre les traits sanguins et physiologiques des races mixtes de lapins ; pour estimer l'héritabilité et la répétabilité réalisées des traits morphométriques et physiologiques. Les résultats obtenus sont des estimations d'héritabilité faible à élevée (0,13 à 0,99) et de répétabilité (0,07 à 0,90) des paramètres morphométriques et physiologiques de races mixtes de lapins à différents âges ont été obtenues dans cette étude. Les estimations élevées de l'héritabilité pourraient résulter d'un effet génétique additif qui a donné lieu à une forte variabilité génétique. Cela implique que la sélection individuelle entraînera un gain génétique élevé, tandis que la répétabilité de ces caractères étant élevée, cela suggère que la probabilité de répéter ces enregistrements est élevée. D'autres études devraient être menées sur des ensembles de données plus vastes, ce qui permettrait d'obtenir des estimations plus précises de l'héritabilité et de la répétabilité.

Investigation on adaptations of broiler chickens to high dietary free amino acid levels in nitrogen utilisation and plasma amino acid concentrations

ABSTRACT 1. A reduction in crude protein (CP) in feed for broiler chickens necessitates elevated free amino acid (AA) levels to meet the requirement of each AA. This study investigated adaptations following a change to diets with increasing free AA concentrations and possible reasons for the limitation caused by the inclusion of more free AA. 2. Male Ross 308 broiler hatchlings received a starter diet (164 g CP/kg containing 80 g/kg soy protein isolate (SPI)) until d 7. From d 7–22, birds received a diet almost identical to the starter diet or two other diets, where 50% or 100% of digestible AA in SPI were substituted with a free AA mixture. Birds were allocated to metabolism units located in the same barn to determine performance (n = 7 units) and blood traits (n = 14 birds). Total excreta collection was performed on d 7–8, 8–9, 9–10, 11–12, 14–15 and 21–22. Blood samples were collected on d 7, 8, 9, 11, 14 and 21. 3. Average daily weight gain (ADG) and average daily feed intake (ADFI) was unaffected at 50% AA substitution but decreased at 100% AA substitution on d 7–22 (p ≤ 0.001). The 100% substitution led to a decline in ADG and ADFI consistently on all days (p ≤ 0.037) except on d 11–12. A 50% AA substitution resulted in lower ADFI on d 7–8 and 14–15 (p ≤ 0.032). Nitrogen utilisation efficiency (NUE) was on a level of ~ 0.74 and was only affected by treatment up to d 11–12 (p ≤ 0.008). Concentrations of 10, 9, 8, 10 and 4 plasma free AA were affected on d 8, 9, 11, 14 and 21, respectively (p ≤ 0.037). 4. Following a change to diets containing high levels of free AA, NUE and free AA concentrations in the circulation became more balanced within 3 to 7 d. The results suggested that peptide-bound and free AA did not cause different NUE, particularly 3 and 7 d after the diet change.