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As the environments in which livestock are reared become more variable, animal robustness becomes an increasingly valuable attribute. Consequently, there is increasing focus on managing and breeding for it. However, robustness is a difficult phenotype to properly characterise because it is a complex trait composed of multiple components, including dynamic elements such as the rates of response to, and recovery from, environmental perturbations. In this review, the following definition of robustness is used: the ability, in the face of environmental constraints, to carry on doing the various things that the animal needs to do to favour its future ability to reproduce. The different elements of this definition are discussed to provide a clearer understanding of the components of robustness. The implications for quantifying robustness are that there is no single measure of robustness but rather that it is the combination of multiple and interacting component mechanisms whose relative value is context dependent. This context encompasses both the prevailing environment and the prevailing selection pressure. One key issue for measuring robustness is to be clear on the use to which the robustness measurements will employed. If the purpose is to identify biomarkers that may be useful for molecular phenotyping or genotyping, the measurements should focus on the physiological mechanisms underlying robustness. However, if the purpose of measuring robustness is to quantify the extent to which animals can adapt to limiting conditions then the measurements should focus on the life functions, the trade-offs between them and the animal’s capacity to increase resource acquisition. The time-related aspect of robustness also has important implications. Single time-point measurements are of limited value because they do not permit measurement of responses to (and recovery from) environmental perturbations. The exception being single measurements of the accumulated consequence of a good (or bad) adaptive capacity, such as productive longevity and lifetime efficiency. In contrast, repeated measurements over time have a high potential for quantification of the animal’s ability to cope with environmental challenges. Thus, we should be able to quantify differences in adaptive capacity from the data that are increasingly becoming available with the deployment of automated monitoring technology on farm. The challenge for future management and breeding will be how to combine various proxy measures to obtain reliable estimates of robustness components in large populations. A key aspect for achieving this is to define phenotypes from consideration of their biological properties and not just from available measures.

Fetuin A (also known as α2-Heremans–Schmid glycoprotein) is a protein primarily expressed by the liver and secreted into the blood. Previous studies have suggested that plasma concentrations of fetuin A are elevated with impaired growth rate in swine. The present study was designed to examine the relationship of porcine fetuin A with growth rate in the pig and to also elucidate the regulation of fetuin A expression by examining the hormonal and cytokine regulation of fetuin A mRNA abundance in hepatocytes prepared from suckling piglets. Quantitative real-time PCR assay was used to quantify the number of fetuin A mRNA molecules/molecule cyclophilin mRNA. Total RNA was isolated from liver of three different groups of pigs to assess changes in mRNA abundance of fetuin A: normal piglets at day 1, day 7 day 21 or 6 months of age (n=6 for each age); runt and control piglets at day 1 of age (n=4); slow growing and normal growing piglets at 21 days of age (n=8). Following birth, fetuin A gene expression increased from day 1 and 7 of age (P<0.05), and then declined at 21 days of age (P<0.05), with a much greater decline to 6 months of age (P<0.01). Fetuin A mRNA abundance was higher in runt pigs v. their normal birth weight littermates (P<0.05). Similarly, fetuin A gene expression was higher in livers of pigs that were born at a normal weight but that grew much slower than littermates with the same birth weight (P<0.05). Hepatocytes were isolated from preweaned piglets and maintained in serum-free monolayer culture for up to 72 h to permit examination of the influences of hormones, cytokines and redox modifiers on fetuin A mRNA abundance. Fetuin A gene expression was enhanced by glucagon, T3 and resveratrol (P<0.05). Growth hormone, cytokines (interleukin6, tumor necrosis factor-α) and antioxidants (N-acetylcysteine, quercertin) reduced fetuin A mRNA abundance (P<0.05). A role for fetuin A in postnatal development is suggested by the differences in fetuin A mRNA abundance between runt piglets or slow growing piglets and their normal growing sized littermates. The hepatocyte experiments suggest multiple hormones and cytokines may contribute to the regulation of fetuin A during early growth of the pig.

Hypoimmunity and numerous stresses are two major challenges in broiler industry. Nutrient intervention at the specific time of embryonic stage is a feasible way to improve animal performance. This study was conducted to investigate the possible effects of in ovo feeding (IOF) of vitamin C at embryonic age 15th day (E15) on growth performance, antioxidation and immune function of broilers. A total of 240 broiler fertile eggs were randomly divided into two groups (0 and 3 mg injected dose of vitamin C at E15), and new-hatched chicks from each treatment were randomly allocated into six replicates with 10 chicks per replicate after incubation. The results indicated that in ovo vitamin C injection improved the hatchability (P < 0.05) and increased immunoglobulin M (IgM) (at the broiler’s age 1st day, D1), IgG and IgM concentrations (D21), as well as lysozyme activity (D21, P < 0.05) and total antioxidant capacity (D42, P < 0.01) in plasma of broilers. On D21, the splenic expression level of DNA methyltransferase 1 (DNMT1) was up-regulated in vitamin C (VC) group, whereas interleukin (IL)-6, interferon-γ, ten-eleven translocation protein 1 and thymine-DNA glycosylase were down-regulated (P < 0.05). On D42, in ovo vitamin C injection up-regulated splenic expression levels of DNMT1, DNA methyltransferase 3B (DNMT3B) and growth arrest and DNA-damage-inducible protein beta (P < 0.05), whereas down-regulated splenic expression levels of IL-6, tumour necrosis factor-α and methyl-CpG-binding domain protein 4 (P < 0.05). Our findings suggested that IOF of 3 mg vitamin C at E15 could improve, to some extent, the antioxidant activity and immune function in plasma, corresponding with the lower expression of pro-inflammatory cytokines in spleen. However, IOF of vitamin C leading to the changes in the expression of DNA methyltransferases and demethylases may suggest an increased trend of DNA methylation level in spleen and whether DNA methylation variation is associated with the lower expression of pro-inflammatory cytokines in spleen warrants future study.

New strategies must be developed to improve poultry performance and health. One of these strategies is the use of supplementations as sodium butyrate (SB) to improve the physiological status and then increasing the growth performance, but the best period of age in which the addition of SB is more effective on birds is not well understood. Therefore, the aim of this study was to investigate the effect of dietary inclusion of SB supplementation through the first, second or whole growth period on some physiological indices and growth performance of growing Japanese quail. In total, 240 unsexed 1-day-old quail chicks were divided into four groups (three replicates per group of 20 chicks in each). The first group was fed basal diet without SB from 1 to 42 days (control, T1), while SB at a rate of 1 g/kg basal diet was mixed with the feed of the 2nd, 3rd and 4th groups of chicks from 1 to 21 days (SB 1 to 21, T2), 1 to 42 days (SB 1 to 42, T3) and 22 to 42 days (SB 22 to 42, T4) of age, respectively. The results stated that addition of SB significantly improved live BW at 21 days, feed conversion ratio (FCR) and BW gain (BWG) during 1 to 21 days in T2 and T3 groups compared to T1 and T4 groups. During the whole period, group T3 had higher BWG and better FCR than the other groups (T1, T2 and T4). At 21 days, no significant differences among all treatments were detected on haematology and serum biochemistry except total protein and cholesterol. At 42 days, SB supplementation significantly improved most serum constituents, haematological parameters, villus height and width of intestine and morphometry of immune organs. The group fed SB throughout the experiment (T3) showed the best results. In conclusion, it is recommended feeding quail on diets containing SB through the whole growth period to show its affirmative impact on the growth and physiological indices.

Selection programs have enabled broiler chickens to gain muscle mass without similar enlargement of the cardiovascular and respiratory systems that are essential for thermoregulatory efficiency. Meat-type chickens cope with high ambient temperature by reducing feed intake and growth during chronic and moderate heat exposure. In case of acute heat exposure, a dramatic increase in morbidity and mortality can occur. In order to alleviate heat stress in the long term, research has recently focused on early thermal manipulation. Aimed at stimulation of long-term thermotolerance, the thermal manipulation of embryos is a method based on fine tuning of incubation conditions, taking into account the level and duration of increases in temperature and relative humidity during a critical period of embryogenesis. The consequences of thermal manipulation on the performance and meat quality of broiler chickens have been explored to ensure the potential application of this strategy. The physiological basis of the method is the induction of epigenetic and metabolic mechanisms that control body temperature in the long term. Early thermal manipulation can enhance poultry resistance to environmental changes without much effect on growth performance. This review presents the main strategies of early heat exposure and the physiological concepts on which these methods were based. The cellular mechanisms potentially underlying the adaptive response are discussed as well as the potential interest of thermal manipulation of embryos for poultry production.

Exposure of rabbit bucks to summer heat stress reduces their homeostasis and semen quality leading to a temporal subfertility. The potentiality of ethanolic extract of Moringa oleifera leaves (M. oleifera ethanolic extract (MLEE)) to reduce negative impacts of heat stress on physiological and semen quality traits was investigated. A total of 28 adult V-line rabbit bucks were randomly distributed among four experimental groups of seven rabbits each. The first group received water (placebo) and served as a control (M0). The other three groups were given orally MLEE at levels of 50 (M50), 100 (M100) and 150 (M150) mg/kg BW every other day for 12 consecutive weeks during the summer season. Chemical constituents of MLEE were detected by gas chromatography/MS. During the experimental period, ambient temperature and relative humidity were recorded daily and were used to estimate temperature and humidity index. Feed intake, BW, rectal temperature were recorded and blood serum biochemical attributes were determined. Semen samples were collected weekly and were analyzed for semen quality traits. Results showed that MLEE contained high percentages of long-chain fatty acids and antioxidant agents. Feed intake and BW were not affected significantly by the treatment, however rectal temperature was decreased significantly by 0.42°C, 0.24°C and 0.40°C in the M50, M100 and M150 groups, respectively, compared with the M0 group. Treatment with 50 mg/kg BW increased concentration of serum albumin (115%; P<0.05), total antioxidant capacity (132%; P<0.05) and testosterone (160%; P=0.098) as well as seminal plasma initial fructose (127%; P=0.092) compared with the control group. Compared with the control, MLEE supplementation with 50, 100 and 150 mg/kg BW increased significantly sperm concentration by 118%, 151% and 158%, sperm progressive motility by 117%, 120% and 118%, sperm viability by 129%, 137% and 127%, sperm normal morphology by 114%, 113% and 114%, intact acrosome sperm by 109% (on average) and sperm with integrated cell membrane by 109%, 123% and 114%, respectively. In conclusion, MLEE supplementation at a level of 50 mg/kg BW could be effectively used to improve heat tolerance, oxidative status and semen quality of rabbit bucks during summer season.

l-Arginine is a nutritionally essential amino acid for spermatogenesis and plays versatile roles in animal health and can be utilized as a potential agent to improve reproductive performance of boars under high ambient temperature. The present study aimed to determine whether dietary l-arginine could alleviate heat stress-induced infertility in boars. In all, 20 boars (PIC 1040; 248.59±3.84 kg BW and 407.65±6.40 days of age) were selected and randomly assigned to four groups (group 0.0%, basal diet; group 0.6%, 0.8% or 1.0%, basal diet added with 0.6%, 0.8% or 1.0% l-arginine (wt:wt), respectively.) The four diets were made isonitrogenous by addition of appropriate amounts of l-alanine. Boars were pre-fed the corresponding experimental diet for 42 days. Then, the semen characteristics and libido were accessed for 6 weeks during the hot summer period (25.5° to 33.0°C). Results show that dietary l-arginine remarkably improved sperm motility, normality, total sperm number and effective total sperm number. Also, dietary l-arginine improved semen antioxidant capacity, such as decrease of malondialdehyde and 8-Hydroxy-2'-deoxyguanosine content in sperm (P<0.05), increase of the ratio of glutathione and oxidized glutathione, total antioxidant capacity, glutathione peroxidase and catalase activities in seminal plasma (P<0.05). Most of mitochondria contained intact ultrastructure in l-arginine-supplemented group which also accompany with higher ATP content than the 0.0% group. The boars fed 0.8% l-arginine show increased levels of estradiol-17β and testosterone and exhibit improved libido performance than boars in the 0.0% group. Adding dietary l-arginine linearly increased (P=0.002) nitric oxide content (as l-arginine increased). The scrotal surface temperature in the 0.6%, 0.8% and 1.0% group were decreased by 0.9°C, 0.9°C and 0.4°C, respectively, compared with the 0.0% group. l-Arginine levels caused linear effect on semen quality and antioxidant capacity, also caused quadratic effect on libido performance. During the hot summer months, the predicted optimal l-arginine levels for best semen quality and antioxidant capacity was 0.8% to 1.0% and for best libido performance was 0.8%. It can be concluded that l-arginine can be used as an effective agent to alleviate heat stress-induced infertility of boar, and that 0.8% to 1.0% can be considered as the optimum dosage.

The review is based on a compiled data set from studies quantifying liver release of glucose concomitant with uptake of amino acids (AA) and other glucogenic precursors in periparturient dairy cows. It has become dogma that AAs are significant contributors to liver gluconeogenesis in early lactation, presumably accounting for the observed lack of glucogenic precursors to balance estimated glucose need. Until recently, there has been paucity in quantitative data on liver nutrient metabolism in the periparturient period. Propionate is the quantitatively most important glucogenic precursor throughout the periparturient period. However, the immediate post partum increment in liver release of glucose is not followed by an equivalent increment in propionate uptake, because of the lower rate of increment in feed intake compared with the rate of increment in requirements for milk synthesis. The quantitative data on liver metabolism of AA do not support the hypothesis that the rapid post partum increase in net liver release of glucose is supported by increased utilisation of AA for gluconeogenesis. Only alanine is likely to contribute to liver release of glucose through its role in the inter-organ transfer of nitrogen from catabolised AA. AAs seem to be prioritised for anabolic purposes, indicating the relevance of investigating effects of supplying additional protein to post partum dairy cows. Combining data from quantitative and qualitative experimental techniques on L-lactate metabolism point to the conclusion that the quantitatively most important adaptation of metabolism to support the increased glucose demand in the immediate post partum period is endogenous recycling of glucogenic carbon through lactate. This is mediated by a dual site of adaptation of metabolism in the liver and in the peripheral tissues, where the liver affinity for L-lactate is increased and glucose metabolism in peripheral tissues is shifted towards L-lactate formation over complete oxidation.

Within recent years, there has been growing interest in the prediction of bull fertility through in vitro assessment of semen quality. A model for fertility prediction based on early evaluation of semen quality parameters, to exclude sires with potentially low fertility from breeding programs, would therefore be useful. The aim of the present study was to identify the most suitable parameters that would provide reliable prediction of fertility. Frozen semen from 18 Italian Holstein-Friesian proven bulls was analyzed using computer-assisted semen analysis (CASA) (motility and kinetic parameters) and flow cytometry (FCM) (viability, acrosomal integrity, mitochondrial function, lipid peroxidation, plasma membrane stability and DNA integrity). Bulls were divided into two groups (low and high fertility) based on the estimated relative conception rate (ERCR). Significant differences were found between fertility groups for total motility, active cells, straightness, linearity, viability and percentage of DNA fragmented sperm. Correlations were observed between ERCR and some kinetic parameters, and membrane instability and some DNA integrity indicators. In order to define a model with high relation between semen quality parameters and ERCR, backward stepwise multiple regression analysis was applied. Thus, we obtained a prediction model that explained almost half (R 2=0.47, P<0.05) of the variation in the conception rate and included nine variables: five kinetic parameters measured by CASA (total motility, active cells, beat cross frequency, curvilinear velocity and amplitude of lateral head displacement) and four parameters related to DNA integrity evaluated by FCM (degree of chromatin structure abnormality Alpha-T, extent of chromatin structure abnormality (Alpha-T standard deviation), percentage of DNA fragmented sperm and percentage of sperm with high green fluorescence representative of immature cells). A significant relationship (R 2=0.84, P<0.05) was observed between real and predicted fertility. Once the accuracy of fertility prediction has been confirmed, the model developed in the present study could be used by artificial insemination centers for bull selection or for elimination of poor fertility ejaculates.

Among domestic ruminants, goats are renowned for their ability to tolerate water deprivation, water restriction and energy restriction. However, some basic questions regarding their ability to endure water restriction under heat stress are still open. Three levels of water restriction (56%, 73% and 87% of the ad libitum) were imposed on 20 cross-bred 3-year-old female goats (75% German Fawn and 25% Hair Goat) distributed into four groups, with five animals per treatment. The experiment was conducted from the beginning of July to the end of August in a farm located in the Eastern Mediterranean region of Turkey (40 m in altitude; 36 59' N, 35 18'E), in which subtropical weather conditions prevail. The average daily temperature during the experiment was 34.2°C, whereas the highest and lowest temperatures were 42°C and 23.1°C, respectively. The average relative humidity was 68.2% and wind speed was 1.2 km/h. Weekly average thermal heat indexes during the experiment were 78.3 (week 1), 79.1 (week 2), 80.1 (weak 3), 79.8 (weak 4), 81.3 (weak 5) and on average 79.7. Feed intake, heart rate, thermoregulatory responses (rectal temperature, respiration rate), blood plasma concentrations of ions (Na, K), antidiuretic hormone (ADH), metabolites (glucose, cholesterol, creatinine and urea) and behavioral aspects (standing, walking, lying) were studied over 30 days. The responses to water restriction were proportional to the level of restriction. The reductions in feed intake (up to 13%), BW (up to 4.6%) and the increases in rectal temperature (0.5°C) and breath rate (10 respirations/min) were moderate and also were far from responses encountered under severe heat and water stresses. The increase in plasma Na (from 119 to 140 mM) and ADH concentrations (from 12.6 to 17.4 pg/ml) indicates that the physiological response to water restriction was in response to mild dehydration, which also explains the increase in blood plasma concentrations of glucose, cholesterol, creatinine and urea. Behavioral responses (reduction in walking from 226 to 209 min/day and increase in lying from 417 to 457 min/day) were associated with conservation of energy or thermoregulation (reducing the exposure to direct radiation).