The impact of digestible lysine and sulfur amino acids on eggshell quality and egg weight control in old ISA brown hens during 62 to 74 wk.

Modifying dietary amino acids has been proposed as a strategy to improve eggshell quality by slowing down increases in egg weight (EW). This study aimed to investigate the effects of different levels of digestible lysine (dLYS) and ratios of digestible sulfur amino acids (dTSAA) to dLYS on performance and eggshell quality in ISA brown hens. A total of 288 hens were individually housed and assigned to 8 treatments, which combined 2 levels of dLYS (5.9 and 5.5 g/kg) with 4 ratios of dTSAA:dLYS (90, 85, 80, and 75) in a factorial arrangement. The study lasted 12 wk, starting at 62 wk of age. The number of eggs was not affected by the interaction between dLYS and dTSAA:dLYS or their main effect. However, the interaction between dLYS and dTSAA:dLYS showed that reducing the dTSAA:dLYS ratio from 85 to 75 when hens were fed 5.5 g/kg of dLYS resulted in a lower EW. Conversely, when hens were fed 5.9 g/kg of dLYS, no significant difference was found in EW among the different ratios of dTSAA:dLYS. Although there was no interaction between the levels of dLYS and dTSAA:dLYS on eggshell quality, reducing the dLYS level from 5.9 to 5.5 slowed down the deterioration in eggshell-breaking strength and eggshell thickness, regardless of the dTSAA:dLYS ratio. These findings suggest that adjusting dietary dLYS while maintaining the dTSAA:dLYS ratio of no less than 85 may be an effective strategy for decelerating the deterioration of eggshell quality in laying hen operations without impacting the egg production rate.

Dietary Intake and Genetic Background Influence Vitamin Needs during Pregnancy.

Numerous approaches demonstrate how nutritional intake can be sufficient to ensure the necessary supply of vitamins. However, it is evident that not all vitamins are contained in all foods, so it is necessary either to combine different food groups or to use a vitamin supplement to be well-fed. During pregnancy, deficiencies are often exacerbated due to increased energy and nutritional demands, causing adverse outcomes in mother and child. Micronutrient supplementation could lead to optimal pregnancy outcomes being essential for proper metabolic activities that are involved in tissue growth and functioning in the developing fetus. In order to establish adequate vitamin supplementation, various conditions should be considered, such as metabolism, nutrition and genetic elements. This review accurately evaluated vitamin requirements and possible toxic effects during pregnancy. Much attention was given to investigate the mechanisms of cell response and risk assessment of practical applications to improve quality of life. Importantly, genetic studies suggest that common allelic variants and polymorphisms may play an important role in vitamin metabolism during pregnancy. Changes in gene expression of different proteins involved in micronutrients' metabolism may influence the physiological needs of the pregnant woman.

A protein-free chemically defined medium for the cultivation of various micro-organisms with food safety significance.

AIMS: To develop a broadly applicable medium free of proteins with well-defined and reproducible chemical composition for the cultivation of various micro-organisms with food safety significance. METHODS AND RESULTS: The defined medium was designed as a buffered minimal salt medium supplemented with amino acids, vitamins, trace metals and other nutrients. Various strains commonly used for food safety research were selected to test the new defined medium. We investigated single growth factors needed by different strains and the growth performance of each strain cultivated in the defined medium. Results showed that the tested strains initially grew slower in the defined medium compared to tryptic soy broth, but after an overnight incubation cultures from the defined medium reached adequately high cell densities. CONCLUSIONS: The newly designed defined medium can be widely applied in food safety studies that require media with well-defined chemical constituents. SIGNIFICANCE AND IMPACT OF THE STUDY: Defined media are important in studies of microbial metabolites and physiological properties. A defined medium capable of cultivating different strains simultaneously is needed in the food safety area. The new defined medium has broader applications in comparing different strains directly and provides more reproducible results.

The TOR pathway participates in the regulation of growth development in juvenile spotted drum (Nibea diacanthus) under different dietary hydroxyproline supplementation.

Commonly used aquatic feed naturally contains low-level or no hydroxyproline (Hyp). This study was conducted to evaluate the effects of dietary Hyp inclusion on growth performance, body composition, amino acid profiles, blood biochemistry, and the expression of target of rapamycin (TOR) pathway-related genes in juvenile Nibea diacanthus. Fish with similar size (initial body weight, 133.00 ± 2.14 g) were fed six isonitrogenous and isolipidic practical diets supplemented with graded levels of Hyp (0, 5, 10, 15, 20, and 25 g kg-1 of dry matter) for 8 weeks. The results indicated that growth performance and feed utilization were improved with increased levels of dietary Hyp (P < 0.05), and the optimum amount of dietary Hyp estimated from SGR as 16.6 g kg-1. The crude protein of whole body and swim bladder and the amino acid composition of muscle and swim bladder were significantly (P < 0.05) affected by the addition of dietary Hyp, which reflects the important role of feed composition in animal body composition. In addition, the expression levels of mammalian target of rapamycin (TOR) and ribosomal protein S6 kinase1 (S6K1) genes in the liver, muscle, and swim bladder increased with increasing Hyp content of diets, while the mRNA expression level of eukaryotic translation initiation factor 4E-binding protein (4E-BP) gene in these tissues decreased. These results indicated that Hyp improved fish growth and the ability to synthesize proteins, most likely through the TOR pathway. It is suggested that dietary Hyp supplementation is particularly necessary for application in aquatic feed.

Regulatory Role of Amino Acids in Pigs Fed on Protein-restricted Diets.

The high inclusion of dietary protein and the imbalance of amino acid (AA) composition in animal husbandry result in inefficient utilization of protein resources and increased nitrogen excretion. Therefore, an efficient approach to alleviate the nitrogen excretion and increase the utilization of protein resources is to formulate the AA-balance protein-restricted diet with crystalline AA supplementation. Nowadays, it is essential to thoroughly understand the regulatory mechanisms of AAs on body metabolism and their vital roles in protein-restricted diets. Besides, an establishment of the amino acid balanced protein-restricted diet system is beneficial for the maintenance of healthy environment and sustainable animal husbandry. This review focused on the recent advances on functional roles of AAs and development of a protein-restricted diet system in animal husbandry.

Food sources of vitamin D and their association with 25-hydroxyvitamin D status in Dutch older adults.

Various populations are at increased risk of developing a low vitamin D status, in particular older adults. Whereas sun exposure is considered the main source of vitamin D, especially during summer, dietary contributions should not be underestimated. This study aims to identify food sources of vitamin D that associate most strongly with serum vitamin D concentration. Data of 595 Dutch adults, aged ≥65 years, were analysed. Vitamin D intake was assessed with a food frequency questionnaire and 25-hydroxyvitamin D (25(OH)D) was determined in serum. Associations of total vitamin D intake and vitamin D intake from specific food groups with serum 25(OH)D status were examined by P-for trend analyses over tertiles of vitamin D intake, prevalence ratios (PRs), and spline regression. The prevalence of vitamin D deficiency was high, with 36% of the participants having a 25(OH)D status <50nmol/L. Participants with adequate 25(OH)D concentrations were more likely to be men and more likely to be younger than participants with vitamin D deficiency. Total median vitamin D intake was 4.3µg/day, of which 4.0µg/day was provided by foods. Butter and margarine were the leading contributors to total vitamin D intake with 1.8µg/day, followed by the intake of fish and shellfish with 0.56µg/day. Participants with higher intakes of butter and margarine were 21% more likely to have a sufficient 25(OH)D status after adjustment for covariates (T1 vs. T3: PR 1.0 vs. 1.21 (95%CI: 1.03-1.42), P-for trend 0.02). None of the other food groups showed a significant association with the probability of having a sufficient 25(OH)D status. This study shows that vitamin D intake was positively associated with total serum 25(OH)D concentration, with butter and margarine being the most important contributors to total vitamin D intake.

Antioxidant nutrition in Atlantic salmon (Salmo salar) parr and post-smolt, fed diets with high inclusion of plant ingredients and graded levels of micronutrients and selected amino acids.

The shift from marine to plant-based ingredients in fish feeds affects the dietary concentrations and bioavailability of micronutrients, amino acids and lipids and consequently warrants a re-evaluation of dietary nutrient recommendations. In the present study, an Atlantic salmon diet high in plant ingredients was supplemented with graded levels of nutrient premix (NP), containing selected amino acids, taurine, cholesterol, vitamins and minerals. This article presents the results on the antioxidant nutrients vitamin C, E and selenium (Se), and effects on tissue redox status. The feed ingredients appeared to contain sufficient levels of vitamin E and Se to cover the requirements to prevent clinical deficiency symptoms. The body levels of α-tocopherol (TOH) in parr and that of Se in parr and post-smolt showed a linear relationship with dietary concentration, while α-TOH in post-smolt seemed to be saturable with a breakpoint near 140 mg kg-1. Ascorbic acid (Asc) concentration in the basal feed was below the expected minimum requirement, but the experimental period was probably too short for the fish to develop visible deficiency symptoms. Asc was saturable in both parr and post-smolt whole body at dietary concentrations of 190 and 63-89 mg kg-1, respectively. Maximum whole body Asc concentration was approximately 40 mg kg-1 in parr and 14 mg kg-1 in post-smolt. Retention ranged from 41 to 10% in parr and from -206 to 12% in post-smolt with increasing NP supplementation. This indicates that the post-smolts had an extraordinarily high consumption of Asc. Analyses of glutathione (GSH) and glutathione disulphide (GSSG) concentrations and the calculated GSH based redox potentials in liver and muscle tissue, indicated only minor effects of diets on redox regulation. However, the post-smolt were more oxidized than the parr. This was supported by the high consumption of Asc and high expression of gpx1 and gpx3 in liver. Based on the present trials, the recommendations for supplementation of vitamin C and E in diets for Atlantic salmon are similar to current practices, e.g. 150 mg kg-1 of α-TOH and 190 mg kg-1 Asc which was the saturating concentration in parr. Higher concentrations than what would prevent clinical deficiency symptoms are necessary to protect fish against incidents of oxidative stress and to improve immune and stress responses. There were no indications that the Se requirement exceeded the current recommendation of 0.3 mg kg-1.