Journal of Animal Physiology and Animal Nutrition最新文献

The aim of this study was to compare milk production, milk components and feed intake of Fleckvieh, Brown Swiss and Fleckvieh × Red Holstein dairy cows kept under identical feeding and management conditions. The study examined efficiency parameters in relation to feed, energy, protein, and metabolic weight of the three breeds. Additionally, the changes of body condition throughout the lactation were assessed using body condition score and back fat thickness. Data collected from 24 feeding trials conducted at the Bavarian State Research Center for Agriculture between 2011 and 2023 were compiled. Totally, 99,288 daily observations from 212 Fleckvieh, 127 Brown Swiss and 103 Fleckvieh × Red Holstein dairy cows were evaluated. Although Brown Swiss is a more dairy orientated breed compared with Fleckvieh as dual-purpose breed, daily milk yield and energy-corrected milk production were not affected by genotype. Brown Swiss was characterized by a significantly (p < 0.05) higher fat and protein content, somatic cell score, and milk urea content. At the same time, Brown Swiss achieved significantly (p < 0.05) lower values for dry matter intake and therefore consumed a lower amount of protein and energy per day. Due to these differences, the calculated efficiency parameters for Brown Swiss were significantly higher in the present study, making Brown Swiss more efficient in terms of feed, energy, protein, and metabolic weight. The differences in efficiency can be partly explained by differences in body weight and the associated maintenance requirements. The higher milk urea values combined with lower protein intake of Brown Swiss compared with Fleckvieh under same conditions, confirm current research findings and indicate physiological differences of the Brown Swiss breed. From this perspective, it is worth considering whether the reference values for milk urea should be adjusted according to breed, as milk urea values are indicators of nitrogen supply to rumen microbes, the protein supply status of cows, and the estimation of nitrogen excretion.

We assessed the suitability of a willow cultivar for monogastric herbivores in zoos using a rabbit model. Thirty-six male New Zealand White × Californian rabbits at 5 weeks of age were provided with bark and leaf material from a willow cultivar, Salix miyabeana (SX61), in one of four treatments for 6 weeks: UC (unrestricted control of pelleted diet); RC (restricted control of pelleted diet); TL (restricted pellets + fresh willow leaf material); and TB (restricted pellets + fresh willow bark material). Daily feed intake and weekly weights were recorded. Fasted blood samples were taken between 8:00 and 11:00 h, and blood biochemistry and acute phase protein (APP) were quantified at the start and end of the study. After the 6-week study period, rabbits were euthanized, and liver and kidney weights were obtained to assess hepatocellular damage. Blood biochemistry results were mainly within reference ranges and suggest a lack of toxicity or cellular damage due to feeding different amounts of willow ingredients. Greater weight gain was observed in the UC group when compared to the RC (p < 0.01), TB, and TL (p < 0.05) groups at the end of the treatment period. Total dry matter (DM) intake was greater in both TB and TL treatment groups when compared to the RC group but lower than the UC group (p < 0.05) across the treatment period. At the end of the study, phosphorus, magnesium, glucose, and AST were lower in the RC group when compared to all other treatment groups (p < 0.05) with a greater blood urea nitrogen than the TL and TB groups (p < 0.01). The TL group had greater blood potassium concentrations and a lower Na:K ratio than the UC and TB groups (p < 0.01). No differences were observed in the APP response over time and among groups; only fibrinogen was greater in the RC compared to the TB group (p < 0.05). The relative liver weight was higher in the UC group when compared to TB (p < 0.05). Given these results, willow bark and leaves at a high dietary inclusion can be considered safe and effective forage materials for monogastric herbivores in zoos.

It is generally accepted that plasma muscle enzyme activity of creatine kinase (CK) and aspartate aminotransferase (AST) may increase in racehorses after exercise and racing, indicating muscle fibre damage and/or increased leakage from muscle fibres. However, other studies suggest that starch intake might influence plasma muscle enzyme activity reported postexercise. This study aimed to evaluate the effect of different starch allowances on plasma muscle enzyme activity in Standardbred trotters in professional training. Seventy-six horses from five professional trainers were sampled pre- and postexercise. The trainers had different feeding strategies and fed various amounts of starch to their horses. Postexercise plasma AST activity was higher (p < 0.007) for the high (H) and medium (M) starch allowances (451–967 and 988–1429 g/day, respectively) than for horses with low starch allowances (L) (0–268 g/day) (H:8.1 ukat/L (SE 0.5); M: 8.4 ukat/L (SE 0.5); L: 5.8 ukat/L (SE 0.7) (p < 0.007)). Postexercise plasma CK activity was higher (p < 0.01) for the medium starch allowance group than for the high and low starch allowance groups (H:4.6 ukat/L (SE 0.3); M: 5.9 ukat/L (SE 0.4); L: 3.9 ukat/L (SE 0.4)). In conclusion, this study showed higher plasma muscle enzyme activity of AST and some elevations in CK activity in horses fed high-starch allowances compared to horses fed low allowances or no starch. In addition, muscle enzyme activity increased in response to the duration of high-intensity exercise. Management systems aiming for low levels of plasma muscle enzyme activity could accordingly offer diets with low starch (< 450 g/day) contents and perhaps training regimes with shorter durations of high-intensity exercise. However, the mechanisms behind and the elevations' biological importance, need further investigation.

Probiotics are increasingly used in poultry nutrition because of their potential to improve performance and reproductive outcomes. However, there is limited consensus on the effectiveness of different probiotic strains and formulations in broiler breeder hens. This meta-analysis aimed to evaluate the impact of various probiotics on broiler breeder performance and reproductive traits. A comprehensive data set on probiotic supplementation in poultry broiler breeder hens (of different strains) was compiled spanning the time period from 1990–2024. The effect size (Hedge's g) of probiotics was analysed to estimate the random and fixed effects of study variations. Among the rooster strains, the Hubbard strain presented a significant reduction in the number of dead sperm (p < 0.01). Moreover, multistrain probiotics were found to be more effective than single strains (p < 0.01). In hens, probiotics were associated with a significantly lower feed conversion ratio (FCR) (p < 0.001), as were improvements in the fertility and hatchability of settable eggs (p < 0.001). In particular, the addition of probiotics derived from Bacillus subtilis significantly increased fertility and hatchability (p < 0.001). In summary, both single-strain and multistrain probiotics significantly increase various reproductive and performance parameters in broiler breeders, with multistrain probiotics consistently showing superior effects across multiple areas. The inclusion of multistrain probiotics up to 1 g/kg generally yielded positive effects on several parameters in broiler breeder hens. These findings support the inclusion of probiotics, particularly multistrain formulations, to increase reproductive efficiency and performance in broiler breeders, providing a sustainable alternative to antibiotics.

Despite its role in energy and amino acid (AA) metabolism, no work has investigated creatine (Cr) content in commercial cat food. This study evaluated the Cr, creatinine (CrN), crude protein (CP) and AA concentrations of 30 commercial extruded cat diets. Further, the AA and CP concentrations were used to determine the indispensable amino acid scores (AAS) of the same diets. Diets were classified as grain-free (GF; n = 15) or grain-based (GB; n = 15), then analysed for Cr, CrN, and AA using high-performance liquid chromatography and CP using a nitrogen analyser. Dietary AA and CP concentrations were used to calculate the AAS of each diet, using the recommended allowance for AA requirements from the National Research Council (NRC 2006) and recommendations from the Association of American Feed Control Officials (AAFCO 2023) as reference patterns. Differences in Cr and CrN contents were analysed using PROC GLIMMIX in SAS. The GF diet category exhibited greater (p < 0.05) concentrations of Cr and CrN compared to GB. The most prevalent limiting AA were aromatic AA (AAA) (59%), followed by sulfur AA (SAA) (30%). These findings provide insight into the Cr content in extruded diets, prompting further investigation into the optimal Cr intake required to support AA and energy metabolism in cats.

Yaks (Bos grunniens) have developed numerous mechanisms to cope with hypoxic environments. Still, as their milk yield is low, the use of production systems building on dairy breeds at high altitude might increase efficiency, but this has not yet been explored. The purpose of the study was, therefore, to quantify the differences in performance and physiology between Bos taurus breeds and yaks when kept under hypoxic conditions for their entire lifetime. We compared 20 mid-lactating Holstein cows and yaks each born and kept at about 4000 m of altitude using exactly the same experimental diet. The Holstein cows produced 5.7 times as much energy-corrected milk (ECM) at a feed efficiency (kg ECM/kg dry matter intake) being 2.63 times that of the yaks (both p < 0.001). Ruminal ammonia (p < 0.001) and blood urea nitrogen concentrations (p = 0.008) were higher in Holstein cows than yaks. Neutral detergent fibre digestibility was lower (p = 0.017) in the Holstein cows (p < 0.001), but not organic matter digestibility. Their blood had lower haemoglobin, haematocrit, and red blood corpuscular indices (all p < 0.001), a higher respiratory rate (p < 0.001), lower O₂ saturation (95 vs. 99%; p = 0.001) and higher HCO³⁻ (p = 0.023) and total CO₂ levels (p = 0.005) than that of the yaks. Immune system-related traits did not differ, and most indicators of metabolic energy supply were similar in both animal types. In conclusion, the Holstein cows outcompeted the yaks in milk production efficiency at high altitude, but this at cost of mild hypoxia during lifetime and the problem that establishing this production system required a diet where all components had to be transported for long distances from the lowlands.