Dietary Content Research Articles

Dietary L-Lysine Requirement of Coho Salmon (Oncorhynchus kisutch) Alevins

The suitable dietary L-lysine concentration for coho salmon (Oncorhynchus kisutch) alevins was assessed by a dose response feeding trial. Six experimental diets were made with graded L-lysine concentrations of 2.29%, 2.81%, 3.32%, 3.80%, 4.27%, and 4.78% of the dry matter, respectively, each of which was fed to triplicate groups of 100 alevins (initial body weight: 0.30 ± 0.01 g) in 18 plastic baskets (water volume 240 L). The alevins were cultured in a flowing freshwater system and fed manually to apparent satiation four times a day for 12 weeks. The survival rate of alevins did not differ significantly among the dietary groups. The specific growth rate (SGR), protein efficiency ratio (PER), and body protein deposition (BPD) increased significantly (p < 0.05) with the increase in dietary lysine concentration up to 3.80% and then reduced as lysine level further increased. The feed conversion ratio (FCR) had an inverse trend to SGR. The whole-body crude protein content of the alevins increased significantly with increasing dietary lysine level, while crude lipid content showed the opposite trend. In comparison, the contents of morphological indices, whole-body moisture, and ash were not affected significantly (p > 0.05) by the different dietary lysine concentrations. The highest contents of lysine, arginine, and total essential amino acids (EAAs) were observed in the group with 4.27% dietary lysine concentration, which did not differ significantly from those in the 3.32%, 3.80%, and 4.78% groups but was significantly higher than those in the 2.29% and 2.81% groups. Similarly, valine had the highest content in the group with 4.78%. The variations in dietary lysine had no significant impacts on other EAA and non-EAA contents except glycine, which increased with increasing dietary lysine level. Second-order polynomial model analyses based on SGR, PER, BPD, and FCR evaluated the optimum L-lysine requirements of coho salmon alevins as 3.74%, 3.73%, 3.91%, and 3.77% of the diet or 6.80%, 6.78%, 7.11%, and 6.85% of dietary proteins, respectively.

Interplay between diet, circulating indolepropionate concentrations and cardiometabolic health in US populations

ObjectivesTo identify indolepropionate (IPA)-predicting gut microbiota species, investigate potential diet–microbiota interactions, and examine the prospective associations of circulating IPA concentrations with type 2 diabetes (T2D) and coronary heart disease (CHD)...

Effects of Aurantiochytrium acetophilum as a source of docosahexaenoic acid for juvenile Atlantic salmon (Salmo salar) on growth, nutrient apparent digestibility, tissue fatty acid composition and expression of lipid metabolism-related genes

Thraustochytrids are a group of unicellular marine protists that are noted for their ability to produce high amounts of lipids, especially docosahexaenoic acid (DHA), making them a valuable source for replacing fish oil in aquafeeds. Varying levels of Aurantiochrytrium acetophilum meal (TM) were evaluated as replacement of fish oil in extruded diets for juvenile Atlantic salmon on growth, nutrient apparent digestibility, fatty acid composition in muscle and liver and expression of genes associated with lipid metabolism. Four experimental diets were tested: a control diet without the inclusion of A. acetophilum meal and three experimental diets derived from the control diet, in which fish oil was progressively replaced by the addition of A. acetophilum meal at 2.5% (TM 2.5), 6.5% (TM 6.5) and 12% (TM 12) respectively. After 12 weeks of feeding, the growth, feed conversion, condition factor and survival of the fish were not affected by the inclusion of A. acetophilum in the diet. However, the 12% inclusion significantly decreased the viscerosomatic index of the fish and the digestibility of protein, lipids, ash and energy compared to the other experimental diets. The lipid content and fatty acid profile of the liver and muscle were significantly affected by diet composition. In both tissues, fish fed the TM 12 diet retained the highest levels of DHA. However, it was also observed that EPA concentrations lessened with increasing dietary content of A. acetophilum meal. Finally, the decrease in the expression of Δ5fad in the fish fed with the TM 6.5 and TM 12 diets showed that fish do not require a higher expression of this desaturase for DHA production, due to the high content of this fatty acid in A. acetophilum meal.

Estimation of digestible zinc and copper in pigs: a meta-analysis approach

The objective of this study was to quantify the impact of Zn and Cu supplementation and nutritional factors on the digestible content of these minerals using a meta-analysis approach. A database derived from 24 publications and describing 142 experimental treatments was compiled. A model showed that positive effects of chelated, (linear and quadratic, P < 0.01) and inorganic Zn supplementation ( P < 0.05) (linear and quadratic, P < 0.01), Zn from ingredients (linear, P < 0.01) and a negative linear effect of dietary Cu concentration ( P = 0.067; R2= 94%) on digestible Zn content. In other model, addition of phytase showed linear improvement of digestible Zn ( P < 0.01; R2= 96%). For digestible Cu, a model showed that chelated and inorganic Cu supplementation ( P < 0.01) linearly increased digestible Cu while dietary Zn level decreased it ( P < 0.01; R2 = 93%). Dietary phytase did not impact digestible content of Cu. The digestibility of Zn and Cu depends on dietary supplementation of these minerals in diets but also on the interaction between these minerals. Finally, phytase supplementation improves digestible Zn content but not Cu.

Long-Term Feeding of Dairy Goats with 40% Artichoke by-Product Silage Preserves Milk Yield, Nutritional Composition and Animal Health Status.

The aim of this work is to study the effect of 40% inclusion of artichoke by-product silage (AB) in dairy goat diets on milk yield, composition and animal health status during a full lactation period compared to an isoenergetic and isoproteic mixed ration based on alfalfa hay and a cereal and legume mixture. Milk yield was not affected by the dietary treatments, and neither was body weight. AB treatment reduced whey protein (0.38 vs. 0.42%, p < 0.05) and milk urea concentrations (687 vs. 773 mg/L, respectively, p < 0.001), and did not affect total true protein (3.22 vs. 3.24% p > 0.05) or other macro-composition variables. AB treatment showed higher milk concentrations of Ca (p < 0.05), Mn (p < 0.01), Cu (p < 0.01) and Zn (p < 0.001) compared to the control group (C). Slight differences were observed in milk fatty acid profile without any negative effects (p > 0.05) on the blood cholesterol and glucose of goats. The AB group reduced blood urea due to its high dietary total phenol content. However, it had a positive effect on β-hydroxybutyrate (p < 0.05) and nonesterified fatty acids (p > 0.05). It was concluded that 40% artichoke by-product inclusion in dairy goat feed for the whole lactation period (23 weeks) is a sustainable solution, reducing feeding cost by 12.5% per kg of dry matter, contributing to a better circular economy without any negative repercussions on the productivity and health of Murciano-Granadina dairy goats.

Effects of dietary vitamin E and C co-supplementation on growth performance, hemato-immunological indices, digestive enzymes activity, and intestinal histology of rainbow trout fed diet contained spoiled fish meal and oil

An eight-week feeding trial was conducted to elucidate the effects of diets containing oxidized fish oil (OFO) and/or spoiled fish meal (SFM) supplemented with various contents of vitamins E (VE: 100 and 200 mg/kg) and C (VC: 200 and 400 mg/kg) on some selected physiological parameters of juvenile rainbow trout, Oncorhynchus mykiss. The growth indices were affected by OFO and SFM-contained diets; the lowest values were observed in those fish raised on diet containing OFO and high levels of the vitamins. In all experimental groups, the hematological parameters (erythrocytes, leukocytes, hematocrit, and hemoglobin) were increased compared to the control group, and higher values were recorded in group fed OFO+VE (200 mg/kg) +VC (400 mg/kg)-supplemented diet (P < 0.05). A significant increase in serum lysozyme activity, immunoglobulin content, and complement pathway, was observed in fish fed OFO or SFM-contained feeds compared to the control group (P < 0.05). Digestive enzyme activities were mainly affected by dietary OFO contents, where the highest activities were detected in fish fed contained OFO and the vitamins (P < 0.05). According to the histological results, vitamin supplementation of OFO or SFM contained diets, especially at higher concentration, effectively reduced intestinal tissue damage (P < 0.05). In conclusion, VE and VC supplementation could mitigate the adverse effects of dietary OFO or SFM (e.g., decreased fish performance or health) by improving physiological responses of rainbow trout.

Cholesterol Behind the Whole Life of Humans

Cholesterol is a sterol, synthesized by animal cells and vital lipid molecule for human cells (animal) and is also a component of the diet, being present in food of animal origin. Its main function is to maintain the integrity and fluidity of cell membranes and to serve as a precursor for the synthesis of substance that are vital for the organism including steroid hormones, bile acids and vitamin D. animal cells acquire cholesterol from extracellular lipoprotein and form new synthesis of cells. Dietary cholesterol comes exclusively from animal sources, it is naturally present in our diet and tissues. Cholesterol is synthesized in the human body in order to maintain a stable peel when dietary intake is low, given the necessity for cholesterol, very effective intestinal uptake mechanisms bile acid and cholesterol reabsorption cycles exist1. Conversely carbohydrates are poorly absorbed and indeed rapidly excreted. Dietary cholesterol content does not significantly influence cholesterol value, which are regulated by various nutritional. Factors that influence cholesterol absorption (or) synthesis. Recent study data do not support a link between dietary cholesterol and cardio vascular diseases2.

The effects of dietary iodine content, milking system, and farming practices on milk iodine concentration and quality traits

Various management practices can influence milk quality traits in dairy cattle. As an example, an increasing investment in automatic milking system to substitute milking parlors has been observed in the last 2 decades in dairy farms which could have affected certain bulk milk quality traits. What is more, milking practices can also affect certain milk parameters; as an example, teat disinfectants containing I are used in commercial farms where pre- or postdipping is performed, leading to presence of some I in the bulk milk. However, this trace mineral is also supplied in cows' diet to fulfill their nutritional requirements, partly contributing to the milk I final concentration. Therefore, the aim of this study was to evaluate the sources of variation of milk I along with other traditional milk quality traits. A total of 91 dairy farms in northeastern Italy were enrolled in the study. In each farm, diet and bulk milk samples were collected on the same day for chemical analysis. Concentration of I, in particular, was determined in both milk and feed with gold standard. Pearson correlations were calculated among the traits available for milk and diet, and a general linear model was used to test significance of fixed effects (feeding system, milking system, farming system, herd size, herd stage of lactation, and sampling month) on milk quality traits including the I concentration. In the case of milk I, diet I and presence of I-based predipping and postdipping teat disinfect application were also tested as fixed effects. Results showed a positive linear correlation between milk and diet I content (correlation coefficient [r] = 0.78). Although milk I was also positively correlated with lactose content (r = 0.25), dietary I was not correlated with other milk traits. Milk I content was significantly affected by dietary I, I-based predipping teat disinfectant application, and herd composition. Compared with conventional farms, organic farms showed lower protein content and greater somatic cell score (SCS) but similar milk I. Milking system significantly affected only lactose content and SCS of milk. Sampling month was only significant for milk urea nitrogen and herd composition, feeding system, herd size, and herd average days in milk did not modify milk gross composition and SCS. In conclusion, dietary supply of I is the main factor affecting milk I concentration and findings suggest that I level in milk can be naturally improved in dairy cows by modulating the I content in the diet administered. However, further research is needed to evaluate the effect of I-based sanitizers on milk I.

Intestinal and Renal Adaptations to Changes of Dietary Phosphate Concentrations in Rat.

We have studied the role of the intestine, kidney, and several hormones when adapting to changes in dietary P concentration. Normal and parathyroidectomized (PTX) rats were fed pH-matched diets containing 0.1%, 0.6%, and 1.2% P concentrations. 32Pi uptake was determined in the jejunum and kidney cortex brush border membrane vesicles. Several hormone and ion concentrations were determined in the blood and urine of rats. Both jejunum and kidney cortex Pi transport was regulated with 5 d of chronic feeding of P diets in normal rats. Acute adaptation was determined by switching foods on day 6, which was only clearly observed in the kidney cortex of normal rats, with more statistical variability in the jejunum. However, no paradoxical increase of Pi uptake in the jejunum was reproduced after the acute switch to the 1.2% P diet. Pi uptake in the jejunum was parathyroid hormone (PTH)-independent, but in the kidney, the chronic adaptation was reduced, and no acute dietary adaptations were observed. The NaPi2a protein was more abundant in the PTX than the sham kidneys, but contrary to the modest or absent changes in Pi uptake adaptation, the transporter was similarly regulated by dietary P, as in the sham rats. PTH and fibroblast growth factor 23 (FGF23) were the only hormones regulated by all diet changes, even in fasting animals, which exhibited regulated Pi transport despite similar phosphatemia. Evidence of Pi appetite effects was also observed. In brief, our results show new characteristics of Pi adaptations, including a lack of correlation between Pi transport, NaPi2a expression, and PTH/FGF23 concentrations.

The Synergistic Effect of Quince Fruit and Probiotics (Lactobacillus and Bifidobacterium) on Reducing Oxidative Stress and Inflammation at the Intestinal Level and Improving Athletic Performance during Endurance Exercise.

Endurance exercise promotes damage at the intestinal level and generates a variety of symptoms related to oxidative stress processes, inflammatory processes, microbiota dysbiosis, and intestinal barrier damage. This study evaluated the effects of quince (Cydonia oblonga Mill.) and probiotics of the genera Lactobacillus and Bifidobacterium on intestinal protection and exercise endurance in an animal swimming model. Phytochemical characterization of the quince fruit demonstrated a total dietary fiber concentration of 0.820 ± 0.70 g/100 g and a fiber-bound phenolic content of 30,218 ± 104 µg/g in the freeze-dried fruit. UPLC-PDA-ESI-QqQ analyses identified a high content of polyphenol, mainly flavanols, hydroxycinnamic acids, hydroxybenzoic acids, flavonols, and, to a lesser extent, dihydrochalcones. The animal model of swimming was performed using C57BL/6 mice. The histological results determined that the consumption of the synbiotic generated intestinal protection and increased antioxidant (catalase and glutathione peroxidase enzymes) and anti-inflammatory (TNF-α and IL-6 and increasing IL-10) activities. An immunohistochemical analysis indicated mitochondrial biogenesis (Tom2) at the muscular level related to the increased swimming performance. These effects correlated mainly with the polyphenol content of the fruit and the effect of the probiotics. Therefore, this combination of quince and probiotics could be an alternative for the generation of a synbiotic product that improves exercise endurance and reduces the effects generated by the practice of high performance sports.

Multiphase diets may improve feed efficiency in fattening crossbreed Holstein bulls: a retrospective simulation of the economic and environmental impact

Beef industry needs alternative feeding strategies to enhance both economic and environmental sustainability. Among these strategies, adjusting the diet dynamically according to the change of nutritional requirements (multiphase diet) has demonstrated its economic and environmental benefits in pig production systems. Therefore, this retrospective study aims to assess, through simulation, the theoretical economic and environmental benefits of introducing a multiphase diet for crossbreed bulls feeding (one or more diet changes). For this, individual data of BW, BW gain, and daily intake were recorded from 342 bulls during the last fattening period (112 days). These data were used to estimate individual trajectory of energy and protein requirements, which were subsequently divided by individual intake to calculate the required dietary energy and protein concentrations. The area between two functions (i.e., ƒ1: constant protein concentration in the original diet during fattening and ƒ2: estimated protein concentration requirements) was minimised to identify the optimal moments to adjust the dietary concentration of energy and protein. The results indicated that both energy and protein intake exceeded requirements on average (+16% and +28% respectively, P < 0.001), justifying the adoption of a multiphase diet. Modelling the individual trajectories of required metabolisable protein (MP, g/kg DM) during the fattening period resulted in exponential decay model in relation to BW [32120 × exp(−0.026 × BW) + 59.9], while the dietary net energy concentration followed a slightly quadratic model [2.26–0.0026 × BW + 0.000003 × BW2]. Minimisation of the area between curves showed two optimal moments to adjust the diet: at 312 kg and 385 kg of BW, indicating three diet phases: (a) <312 kg, (b) 312–385 kg, and (c) 385–600 kg. For the second and third phases, the dietary energy and protein concentration should be 70 g MP/kg DM and 1.70 Mcal/kg DM and 61 g MP/kg DM and 1.65 Mcal/kg DM, respectively. These diet adjustments might improve economic profitability by 29 €/animal, reduce estimated nitrogen excretions by 16% (P < 0.001), and maintain similar weight gain (P > 0.16) compared to the commercial diet. However, the decrease in dietary energy concentration led to increased fibre concentration, which in turn increased the estimated CH4 emissions of animals with the multiphase diet (+44%, P < 0.001). Hence, multiphase diet could theoretically reduce feeding cost and nitrogen excretion from fattening cattle. Further in vivo studies should confirm these results and find optimal nutritional strategies to improve economic profitability and environmental impact.

Immune function, egg quality and production responses in layer hens fed two different lignocellulose fibre supplements during the early laying period

The effects on immune function and egg productivity of 2 commercial lignocellulose supplements with similar insoluble and soluble fibre concentrations and water holding capacities, were determined in Hy-Line Brown hens from 20 weeks-of-age for 8 weeks. Hens were fed 1 of 3 diets (6 pens/diet, 3 hens/pen): Control diet – a commercial layer diet; Diet LC1 - Control diet plus 1.5 g Arbocel RC fine/100 g diet; Diet LC2, Control diet plus 1.5 g OptiCell C5/100 g diet. After 4 weeks, heterophil phagocytosis index and percentage (innate immunity), was greater in LC1 (p < 0.05) than Controls. After 8 weeks, absolute and relative weights (g/100 g BW) of LC1 thymus glands were heavier (p < 0.05) than Control; numbers of intestinal Peyer’s patches in LC1 were greater (p < 0.05) than LC2 and Control; total and relative areas of LC1 Peyer’s patches were higher (p < 0.05) than Control. Yolk immunoglobulin Y concentrations of LC1 were higher but not significantly, than Control and LC2. Between 6 and 8 weeks, egg weights and eggs produced/hen per d of LC1 hens were greater (p < 0.05) than Controls. Feeding LC1, but not LC2, during early lay significantly improved immune function and egg productivity compared to Control. As dietary fibre concentrations of LC1 and LC2 were similar, differences in their relative concentrations of chemical components such as cellulose and lignin or types of polysaccharides, may have contributed to the improvements during early lay.

The Effects of Dietary Manganese and Selenium on Growth and the Fecal Microbiota of Nursery Piglets.

The objective of this study was to determine the impact of varying dietary manganese and selenium concentrations, antioxidant cofactors, on the growth performance and fecal microbial populations of nursery pigs. The piglets (N = 120) were blocked by weight (5.22 ± 0.7 kg) and sex. The pens (n = 5/treatment) within a block were randomly assigned to diets in a 2 × 3 factorial design to examine the effects of Se (0.1 and 0.3 mg/kg added Se) and Mn (0, 12, and 24 mg/kg added Mn) and were fed in three phases (P1 = d 1-7, P2 = d 8-21, P3 = d 22-35). The pigs and orts were weighed weekly. Fecal samples were collected d 0 and 35 for 16S rRNA bacterial gene sequencing and VFA analysis. The data were analyzed as factorial via GLM in SAS. There was a linear response (p < 0.05) in overall ADG across dietary Mn. Supplementing 24 mg/kg Mn tended to decrease (p < 0.10) the relative abundance of many bacteria possessing pathogenic traits relative to Mn controls. Meanwhile, increasing Mn concentration tended to foster the growth of bacteria correlated with gut health and improved growth (p < 0.10). The data from this study provide preliminary evidence on the positive effects of manganese on growth and gut health of nursery pigs.

Fodder beet: know what you are feeding for a nutritionally balanced diet for dairy cattle

Fodder beet’s (FB) high soluble sugar and low crude protein content provide environmental benefits but also nutritional challenges, making it a unique crop in New Zealand dairy systems. Knowledge of dietary nutrient content is important to inform both mineralsupplementation and type of supplementary feed to offer. This will help ensure nutritional requirements for dairy cows are met, maximising the likelihood of positive outcomes for animal health and production. A database containing 694 samples of FB leaf andbulb tissue was compiled from monitor farm data, research projects, and cultivar evaluation trials with the objective of determining the variability in nutritional content. Descriptive statistics were used to highlight the range and variability in FB leaf and bulb nutritional composition between regions and cultivars. Our results reinforce that FB bulbs (which usually make up 70- 90% of the crop DM) are typically low in crude protein, fibre, phosphorus, calcium, and sulphur, but are high in soluble sugars. The variation in nutrient content between cultivars, and within cultivars both between and within regions shown in this study highlights the importance of paddock-specific feed analyses, and the limitations of textbook values, particularly whole crop values which do not differentiate between bulb and the more nutritionally valuable leaf.

Opposite effects of low-carbohydrate high-fat diet on metabolism in humans and mice

BackgroundLow-carbohydrate diet (LCD) is effective for weight loss and glycaemic control in humans. Here, the study aimed to explore the effects of LCD/high-fat diet (HFD) in both humans and mice.MethodsTwenty-two overweight or obese participants received LCD for 3 weeks. Based on carbohydrate intake > 10% or ≤ 10% of calories, the participants were divided into moderate LCD (MLCD) and very LCD (VLCD) groups. The participants completed a 10-question food preference survey. Meanwhile, C57BL/6J mice were assigned to five groups: chow diet (CD, 10% fat), HFD with 60%, 70%, and 75% fat from cocoa butter (HFD-C), and HFD with 60% fat from lard (HFD-L) and fed for 24 weeks. Eight mice were acclimatised for the food-choice test.ResultsLCD decreased the total energy intake in humans. The VLCD group showed greater weight loss and better glycaemic control than the MLCD group. A food preference survey showed that 65% of participants tended to choose high-carbohydrate foods. In mice, HFD resulted in energy overconsumption, obesity, and metabolic disorders. When CD and HFD-L were administered simultaneously, mice rarely consumed CD. In the HFD-C groups, the energy intake and body weight increased with increasing dietary fat content. Compared with the HFD-C group, the HFD-L group consumed more energy and had poorer metabolism.ConclusionsLower carbohydrate intake contributed to lower energy intake and improved metabolism in humans. In mice, diets with a higher proportion of fat become more attractive and obesogenic by fixing the fat sources. Since the mice preferred lard to cocoa butter, lard induced excess energy intake and poorer metabolism. Different food preferences may be the underlying mechanism behind the opposite effects of the LCD/HFD in humans and mice.Trial registrationThe clinical trial was registered with the Chinese Clinical Trial Registry (www.chictr.org.cn). The registration number is ChiCTR1800016786. All participants provided written informed consent prior to enrolment.

Goat hair as a bioindicator of environmental contaminants and adrenal activation during vertical transhumance.

Autochthonous breeds of livestock are considered a pivotal genetic resource for agriculture, rural development, and food and nutrition security. In the Italian Alps, local livestock breeds are maintained using the traditional alpine farming system based on vertical transhumance, with the use of alpine pastures from late spring to autumn and indoor housing with a hay-based diet for the remaining part of the year. Because of their tight link with the territory of origin, local breeds could be used to biomonitor environmental contaminations. Moreover, animal welfare should also be monitored during transhumance in animals, which are exposed to a sudden farming system change and different types of stressors. For these reasons, this investigation hypothesized that the content of trace elements, heavy metals, and cortisol in the hair of goats changes during vertical transhumance, possibly reflecting different dietary contents and activity of the hypothalamic-pituitary-adrenal (HPA) axis. This study aimed to assess the response of an Italian local goat breed to the change from indoor housing to alpine pasture in summer in terms of hair concentrations of (i) trace elements and heavy metals and (ii) cortisol. The regrown hair of Frisa goats was monthly collected for 2 consecutive years (n = 10 for heavy metals and trace elements and n = 6 for cortisol in 2021, n = 17 for both analyses in 2022), once before vertical transhumance and twice after that event. Hair was then analyzed for trace elements, heavy metals, and cortisol by inductively coupled plasma-optical emission spectrophotometer (ICP-OES) and enzyme immunoassay (EIA), respectively. Data were analyzed by multilevel models. The results showed an increase in As content during alpine pasture (p < 0.01), probably reflecting the soil and water As contents of the grazing area, while Mg, Zn, and Al (p < 0.01) followed the opposite trend, decreasing in the second month after vertical transhumance. Hair cortisol concentrations increased during 2 months of alpine pasture (p < 0.001), indicating an increase in the activation of the HPA axis, in agreement with previous studies. Future investigations can consider a longer study period and the development of ad hoc animal welfare indicators.

PSXI-16 Nitrogen Excretion and Urine Ph in Growing Pigs Decreased By Reducing Dietary Protein Concentrations

Abstract The objective of the present work was to determine effects of reducing dietary crude protein (CP) concentrations with indispensable amino acid (AA) supplementation on nitrogen balance and urinary pH in growing pigs. Three experiments were conducted using 12 barrows with an initial body weight of 29.9, 50.2, and 78.2 kg (standard deviation = 1.8, 2.2, and 3.7, respectively) individually housed in metabolism crates. In each experiment, a quadruplicated 3 × 2 incomplete Latin square design with 3 diets varying CP concentrations in each experiment and 2 periods per square was employed. In experiments 1 and 2, experimental diets based on corn, soybean meal, corn distillers dried grain with solubles, and rapeseed meal were formulated to contain 16.8, 15.0, and 13.2% CP as-fed basis and 16.8, 14.9, and 13.1% CP as-fed basis, respectively. In experiment 3, experimental diets based on corn and soybean meal were formulated to contain 15.1, 13.2, and 11.4% CP as-fed basis. All diets were supplemented with indispensable AA to meet all indispensable AA requirements. Each period consisted of a 5-day adaptation period followed by a 4-day collection period. On days 6 and 10, chromic oxide was added at 0.5% in morning meals as a marker and the marker-to-marker procedure was used for the quantitative collection of feces. Urine collection was initiated at 10:00 on day 6 and terminated at 10:00 on day 10. Polynomial contrasts were performed to test linear and quadratic effects of dietary CP concentrations on the response variables in each experiment. In all experiments, daily N intake was linearly decreased (P &amp;lt; 0.05) with decreasing dietary CP concentrations. Decreasing dietary CP concentrations resulted in linear reduction in daily fecal N excretion (P &amp;lt; 0.05) in experiment 2 and linear reductions in daily urinary N excretion (P &amp;lt; 0.05) in all experiments. Total N excretion linearly decreased (P &amp;lt; 0.05) with decreasing dietary CP concentration in all experiments. The urinary pH obtained from 30- and 50-kg pigs was linearly decreased (P &amp;lt; 0.05) with decreasing dietary CP concentrations. In conclusion, lowering dietary CP concentrations decreased N excretion and urinary pH in 30-, 50-, and 78-kg pigs.

PSXI-17 Prediction Models for Phosphorus Excretion of Pigs

Abstract The objective of the present study was to develop prediction equations for daily phosphorus excretion based on body weight (BW) and dietary phosphorus concentration of pigs. Four experiments were conducted using pigs with an initial body weight of 15 kg, 30 kg, 50 kg, and 78 kg. In the experiment 1, the experimental diets were mainly based on corn, soybean meal, whey powder, fish meal, and blood plasma. In the experiments 2, 3, and 4, the diets based on corn, soybean meal, and fibrous ingredients were formulated. All experimental diets were supplemented with commercial phytase at 500 FTU/kg. In all experiments, a total collection method and the marker-to-marker procedure were used for fecal and urinary collection. Fecal and urinary phosphorus excretions were determined. Correlation coefficients among BW, daily phosphorus intake, and daily phosphorus excretion of pigs were determined. Prediction equations for phosphorus excretion were developed using BW and dietary phosphorus concentration as independent variables. The BW had positive correlations with fecal and total phosphorus excretion (r = 0.78 and P &amp;lt; 0.001 for fecal phosphorus excretion and r = 0.78 and P &amp;lt; 0.001 for total phosphorus excretion). The prediction equations for predicting fecal phosphorus excretion and total phosphorus excretion were: fecal phosphorus excretion (g·pig–1·d–1) = –0.647 – 0.00065 × BW2 + 0.270 × BW × dietary phosphorus concentration (R2 = 0.81; P &amp;lt; 0.001); total phosphorus excretion (g·pig–1·d–1) = –0.619 – 0.00064 × BW2 + 0.277 × BW × dietary phosphorus concentration (R2 = 0.85; P &amp;lt; 0.001) where BW in kg and phosphorus concentration in %. The BW of pigs corresponding to the age was predicted using the NRC model. The mean phosphorus excretion of pigs weighing from 7 kg to 120 kg at day 22 to 180 was calculated using a developed estimation equation, with BW and total phosphorus requirement used as independent variables. Daily fecal and total phosphorus excretions were 3.77 g·pig–1·d–1 and 4.01 g·pig–1·d–1, respectively.

PSVIII-24 Dietary Vitamin D Was Associated with Increased Circulating Vitamin D in Dogs with No Observable Adverse Effect Up to 9,992 Iu/Kg Dry Matter

Abstract Adult dogs have been reported to benefit from circulating 25 (OH) vitamin D above 100 ng/mL to support optimal health. Although there is no consensus for optimum concentrations of circulating vitamin D it has been reported that circulating vitamin D is positively related to a reduced severity of disease, decreased disease risk, enhanced efficacy of treatment and overall positive disease outcome. This association does not prove causality. However, the positive effect of circulating vitamin D suggests that this relationship is not simply an association or a response to disease but reflects a causal supporting function of increased circulating vitamin D above that required for bone health. Understanding the relationship between dietary vitamin D and circulating vitamin D status is essential to progress in using dietary vitamin D to influence health and disease in the dog. Five groups of 8 adult dogs each were fed for 6 months according to AAFCO maintenance protocols to evaluate the influence of dietary vitamin D on circulating vitamin D concentrations and indices of health. Body weight was recorded, and blood samples taken before being fed treatment foods. After initiation of treatment foods, intake was measured daily, body weight was measured weekly, and blood samples were taken initially, after 85 days of feeding, and at the end of the study. The dry matter concentrations of vitamin D (IU/kg) were 796, 3,087, 5,511, 7,314, and 9,992 in approximately 4,000 kcal/kg foods. There were no clinical signs of either deficiency or excess vitamin D. Normal circulating concentrations of hemoglobin, packed cell volume, albumin, total calcium, phosphorus and alkaline phosphatase were maintained in all groups. Circulating vitamin D increased in all groups except those consuming 796 IU/kg. All dogs consuming increased dietary vitamin D had increased concentrations of 25 (OH) D compared with the control group consuming 796 IU/kg. Concentration of calcium increased in all groups with no difference in calcium increase associated with dietary vitamin D. There was no difference in the change in concentration of parathyroid hormone or ionized calcium in response to treatment. Vitamin D increased in a linear and quadratic fashion in response to dietary vitamin D concentration. This resulted in all the dogs fed 5,511 IU/kg and above exceeding 100 ng/mL circulating 25 (OH) D. Dietary vitamin D was positively associated with increased circulating concentrations with no observable adverse effects in dietary concentrations up to 9,992 IU/kg dry matter. This allowed all dogs consuming 5,511 IU/kg and above to exceed the circulating concentration previously recommended for optimal health in dogs.

265 Interactive Effects of Dietary Isoleucine and Valine Ratios to Lysine in Response to Varying Leucine to Lysine Ratios on Pectoralis Major Muscle Protein Expression in Commercial Broilers

Abstract Optimizing the dietary concentrations and ratios of branched-chain amino acids (BCAA) is necessary to optimize broiler chicken growth performance and carcass meat yield. A central composite design (CCD) study was conducted to understand the impact of dietary BCAA concentrations and ratios on Pectoralis major (PM) muscle protein expression involved in mTOR and related protein synthesis pathways as well as and investigate the mechanisms behind how BCAA ratios affect broiler growth and muscle protein accretion. A total of 2,592 d-old Ross 344 × 708 male broilers were randomly placed in 144 floor pens (n = 18 birds per pen). Before the initiation of the experimental finisher phase, all pens were standardized to contain 15 birds per pen. Each pen received 1 of 15 dietary treatments in the 23 CCD with 6 center points from 20 to 35 d of age, varying in digestible ratios of valine:lysine (Val:Lys; 64 to 87), leucine:lysine (Leu:Lys; 110 to 185), and isoleucine:lysine (Ile:Lys; 52 to 75). On d 35, 1 bird per pen was randomly selected for PM protein extraction and proteomic analysis via data independent acquisition protein sequencing with a timsTOF Pro 2 LC/MS/MS and Spectronaut 15 software. Ribosomal protein S6 kinase (RPS6KA3), eukaryotic elongation factor 2 (EEF2), eukaryotic translation initiation factor 4B (EIF4B), eukaryotic translation initiation factor 4E (EIF4E), CAP-Glycine domain containing linker protein 1 (CLIP1), mitogen-activated protein kinase 3 (MAPK3), Protein kinase domain-containing protein (MAP2K1), Dual-specificity mitogen-activated protein kinase kinase 2 (MAP2K2), paxillin (PXN), and regulator complex protein (LAMTOR3) were identified, quantified, and analyzed as a CCD using the RSREG procedure of SAS ver. 9.4 with significance set at P ≤ 0.10. The surface response models for RPS6KA3, EEF2, EIF4B, EIF4E, MAPK3, MAP2K1, MAP2K2, CLIP1, PXN, and LAMTOR3 were not significant (P ≥ 0.926; R2 values ≤ 0.1). No linear (P ≥ 0.5223), quadratic (P ≥ 0.0.634) or cross product (P ≥ 0.6238) regression effects were observed for any of the proteins analyzed. A minimum stationary point was observed for RPS6KA3, EEF2, MAPK3, and LAMTOR3. However, optimal values for the other proteins could not be obtained due to stationary saddle points. Overall, the results in this study indicate that varying concentrations of dietary BCAA may not impact expression of proteins related to broiler skeletal muscle growth on d 35 following the 15-d treatment period, despite the influence on live performance. This is a limitation of this study and suggests that if the mTOR pathway was involved it was not still differentially up- or down-regulated at this time point. Further investigation and new studies with multiple time points will be required to better understand the mechanisms behind how BCAA impact broiler growth and muscle development.