Frank Liebert

Nutritional evaluation of rapeseed protein compared to soy protein for quality, plasma amino acids, and nitrogen balance--a randomized cross-over intervention study in humans.

BACKGROUND & AIMS Plant proteins such as rapeseed have received little attention for human nutrition due to their high level of antinutritive compounds. Today, newer technologies can eliminate such compounds. The present intervention study aimed to evaluate nutritional and physiological properties of two manufactured canola proteins with special focus on their bioavailability in humans. METHODS 28 healthy male subjects (ø 25 years) consumed 30.0 g protein (canola protein isolate--CPI, canola protein hydrolyzate--CPH or soy protein isolate--SPI) in a randomized, double-blind, cross-over study. Blood samples were regularly drawn over the 8-h postprandial period and a 24-h urine sample was collected. RESULTS True digestibility of the canola proteins determined in a separate rat assay showed 93.3% for CPI and 97.3% for CPH. In humans, consumption of either 30.0 g canola protein or soy protein mixed in a drink led to significant increases in plasma amino acids after 62.3 and 83.6 min, respectively. While the CPH produced an earlier response compared to CPI and SPI, total amino acid response (AUC for 8 h) was comparable between all interventions. The nitrogen balance between the three proteins tested showed no statistical differences. CONCLUSIONS High digestibility of rapeseed protein was found in rats. In humans, this is the first intervention study showing rapeseed protein (both isolate and hydrolyzate) as having a high nutritional quality and can be considered to be as efficient as soy protein for a postprandial amino acid response. This trial was registered at ClinicalTrials.gov Identifier: NCT01481584.

Improving the Reliability of Optimal In-Feed Amino Acid Ratios Based on Individual Amino Acid Efficiency Data from N Balance Studies in Growing Chicken.

Simple Summary Dietary amino acid concentration should closely meet the quantitative requirement of animals dependent on genotype, gender, age, aimed performance and housing conditions. Both under- and over-supply yield impaired efficacy of individual amino acid utilization and increase the nitrogen excretion. Hence, for optimal feed formulation, a validated knowledge about adequacy of dietary amino acid balance is necessary. Present studies contribute toward ensuring ideal amino acid ratios in diets for growing broiler chicken making use of a new amino acid efficiency-based procedure. Abstract Three consecutive nitrogen balance experiments with fast-growing male broiler chickens (ROSS 308), both during starter and grower periods, were conducted to determine the ideal ratios of several indispensable amino acids relative to lysine. The control diets based on corn, wheat, fishmeal, field peas, wheat gluten and soybean oil were formulated by computer optimizing to meet the assumed ideal amino acid ratios and to fulfill both the energy and nutrient requirements of growing chicken. According to principles of the diet dilution technique, balanced control diets were diluted by wheat starch and refilled by crystalline amino acids and remaining feed ingredients, except the amino acid under study. The lysine, threonine, tryptophan, arginine, isoleucine and valine diluted diets resulted in significantly lower protein quality as compared to control diet, especially following increased dietary lysine supply (experiments II and III) and stronger amino acid dilution (experiment III). Accordingly, the limiting position of individual amino acids was confirmed, and the derived amino acid efficiency data were utilized to derive ideal amino acid ratios for the starter period: Lys (100): Thr (60): Trp (19): Arg (105): Ile (55): Val (63); and the grower period: Lys (100): Thr (62): Trp (17): Arg (105): Ile (65): Val (79).

Assessing the age-dependent optimal dietary branched-chain amino acid ratio in growing chicken by application of a nonlinear modeling procedure

Based on a nonlinear N utilization model, 2 N balance experiments with growing broiler chickens were conducted, investigating the ideal amino acid (AA) ratio (IAAR) of the branched-chain AA (BCAA) Leu, Ile, and Val related to Lys. In both of the experiments, the starter (I: 10-20 d of age) and grower periods (II: 25-35 d of age) utilized 36 male Ross 308 chickens each (n = 144). Nitrogen balance periods were divided into an adaptation period (5 d) and 2 consecutive collection periods (2 × 5 d). Diets of experiment 1 were based on a consistent mixture of wheat, soy protein concentrate, wheat gluten, fish meal, and crystalline AA, subsequently diluted by wheat starch to provide 8 graded CP levels (6-34% CP). Results of nonlinear regression between N intake and N deposition yielded the theoretical maximum for N deposition (NDmaxT; I: 4,593 mg of N/BWkg(0.67)/d; II: 4,302 mg of N/BWkg(0.67)/d). Furthermore, the daily N maintenance requirement (NMR) was derived (I: 113 mg of N/BWkg(0.67); II: 215 mg of N/BWkg(0.67)/d). Both the age-dependent data for NMR and NDmaxT were applied to calculate the model parameter b (protein quality, independent of N intake) and bc(-1) (efficiency of limiting AA), respectively. Five diets based on the same ingredients as in experiment 1 were formulated for experiment 2: an AA balanced basal diet and 4 diets of the same composition but lacking in supply of Lys, Leu, Ile, or Val. All experimental diets were isocaloric and isonitrogenous. For calculation of the IAAR, observed bc(-1) data of each AA diluted diet were utilized. The concluded IAAR of Lys:Leu:Ile:Val for the starter and grower period were 100:94:55:65 and 100:106:56:72, respectively. These results indicated a higher demand for Leu and Val during the grower phase and, generally, a lower IAAR for the BCAA than previously reported in comparable experiments.

Evaluating the Age-Dependent Potential for Protein Deposition in Naked Neck Meat Type Chicken

Simple Summary Growth rates of fast-growing chickens are reduced by a higher ambient temperature (AT) because of difficulties in dissipating heat through the feather coverage. Naked neck meat type genotypes could be helpful in increasing the tolerance for high AT. However, basic model parameters of this genotype necessary to further assess amino acid requirements are as yet unavailable. The experiments were conducted to estimate both the daily nitrogen maintenance requirement (NMR) and the potential for daily nitrogen retention NRmaxT). These observed model parameters provide the basic information to characterize the growth potential of the genotype for further application in modeling of individual amino acid requirements of naked neck meat type chicken. Abstract The introduction of the naked neck gene (Na) into modern meat type chicken is known to be helpful in increasing the tolerance for a high ambient temperature (AT) by reducing the feather coverage which allows for a higher level of heat dissipation compared to normally feathered (na/na) birds. In addition, reduced feather coverage could affect requirements for sulfur containing amino acids. As a prerequisite for further modeling of individual amino acid requirements, the daily N maintenance requirement (NMR) and the threshold value of daily N retention (NRmaxT) were determined. This was carried out using graded dietary protein supply and exponential modeling between N intake (NI) and N excretion (NEX) or N deposition (ND), respectively. Studies with homozygous (Na/Na) and heterozygous (Na/na) naked neck meat type chicken utilized 144 birds of average weight (50% of each genotype and sex) within two N balance experiments during both the starter (days 10–20) and the grower period (days 25–35). Birds were randomly allotted to five diets with graded dietary protein supply but constant protein quality. The observed estimates depending on genotype, sex and age varied for NMR and NRmaxT from 224 to 395 and 2881 to 4049 mg N/BWkg0.67/day, respectively.

Does the Naked Neck Meat Type Chicken Yield Lower Methionine Requirement Data

Simple Summary It was hypothesized that naked neck chickens could have a lower methionine requirement according to their reduced feather coverage. The hypothesis was examined by nitrogen balance studies and non-linear model application for estimating methionine requirement data of naked neck chickens. It was concluded that naked neck birds do not require less methionine than normally-feathered birds. Abstract Methionine (Met) requirement studies with homozygous (Na/Na) and heterozygous (Na/na) naked neck meat type chicken utilized 144 birds of average weight (50% each genotype and sex) within two N balance experiments involving both the starter (d10–20) and grower period (d25–35). The birds were randomly allotted to five experimental diets with graded protein supply and Met as the limiting amino acid. The proportion of native feed protein sources (soy protein concentrate, maize, wheat, fishmeal and wheat gluten) was kept constant to ensure a uniform protein quality in all diets. The Met requirement depending on genotype, sex, age period and growth performance (protein deposition) was estimated using a non-linear modeling procedure of N utilization in monogastric animals. On average, 0.47% (Na/Na) and 0.45% (Na/na) dietary Met was established as adequate in the starter diet, as well as 0.37% (Na/Na) and 0.36% (Na/na) Met in the grower diet for both of the sexes. In conclusion, the Met requirement of the naked neck chicken is not significantly different from its normally-feathered counterparts. In addition, the low feather production was not reflected by reduced requirement for Met in naked neck birds. However, these conclusions are valid only at the given Met:Cys ratio (1:1) in the experimental diets.

Protein deposition potential and modeling of methionine requirements in homozygous (Na/Na) and heterozygous (Na/na) naked neck meat type chicken

High ambient temperature (AT) decreases the growth of fast growing chicken because of difficulty in dissipating heat through the feather coverage. Consequently, they become more sensitive to high AT (Yunis and Cahaner, 1999). Introduction of the naked neck gene (Na) in modern meat type genotypes could be helpful in tolerating high AT by providing more surface area for heat dissipation compared to their normally feathered (na/na) counterparts. The aims of this study were to determine the (1) protein deposition potential and (2) modeling the methionine requirement for these genetics.

Does the Optimal Dietary Methionine to Cysteine Ratio in Diets for Growing Chickens Respond to High Inclusion Rates of Insect Meal from Hermetia illucens

Simple Summary Currently, several alternative protein sources are under investigation for replacing soybean meal in poultry diets. One alternative is larvae meal of the black soldier fly (Hermetia illucens) with a specific sulfur amino acid composition. The larvae meal is limiting in sulfur amino acids supply and provides a wide methionine:cysteine ratio of 61:39. Currently, it is not known whether the insect meal has an impact on the optimal ratio of methionine to cysteine in broiler chicken diets. The methionine:cysteine ratio significantly influences animal growth and welfare. Both methionine and cysteine excess and deficiency can lead to an impaired feed intake, growth, and feed efficiency. Therefore, the aim of this study was to investigate whether the optimal methionine:cysteine ratio is modulated when a high inclusion rate of partly defatted Hermetia illucens meal is applied. The results show that a methionine:cysteine ratio of 50:50 yields superior growth and dietary protein quality. It can be concluded that the insect meal under study is a promising alternative protein source without modulating the optimal methionine:cysteine ratio in broiler chicken diets. Abstract The dietary methionine:cysteine (Met:Cys) ratio (MCR) is an important factor influencing the optimal growth of chickens. Therefore, this study aimed to contribute to the assessment of the optimal dietary MCR in diets with the complete replacement of soybean meal (SBM) by a partly defatted larvae meal of Hermetia illucens (HM). A growth study with 240 male meat-type chickens (Ross 308) was conducted, also assessing the body nutrient deposition both at the end of the starter (day 21) and the grower (day 35) period. Birds were fed experimental diets based on wheat, maize, and insect meal (23%/21% HM in starter/grower diets). Sulfur amino acids were created as the limiting AA in diets with graded MCR (40:60; 45:55; 50:50; 55:45; 60:40). The control diet contained SBM instead of HM with a MCR of 50:50. The current results based on growth parameters, dietary protein quality, and Met efficiency data gave support to the previous assumption of an ideal MCR of 50:50, which was also valid in diets with a high proportion of insect meal. The lowest MCR of 40:60 led to significantly impaired feed intake and growth of the birds, while the response to the highest MCR (60:40) was moderate.

Ideal isoleucine and valine to lysine ratios in low protein diets for growing pigs

Isoleucine (ILE) or valine (VAL) are considered to be potentially limiting the dietary protein quality in protein reduced pig diets supplemented with L-lysine∙HCl, DL-methionine, L-threonine and L-tryptophan. Consequently, validated dietary ratios of both amino acids (AA) are necessary to ensure optimal feed protein utilization in fast growing pigs. Therefore, the present study with growing fattening pigs was conducted to derive AA efficiency data of ILE and VAL as related to lysine (LYS) in low protein diets to conclude ideal amino acid ratios (IAAR) of ILE, VAL and LYS, respectively.

Assessment of ideal dietary amino acid ratios between branched-chain amino acids for growing chicken

Improvement of amino acid (AA) recommendations are a precondition for sustainable conversion of feed to food proteins and have to be based on physiological acceptable and validated procedures to derive both quantitative daily AA requirements and optimal dietary AA ratios. According to earlier applications of an exponential nitrogen (N)-utilization model (Samadi and Liebert, 2006, 2008; Liebert, 2008), two experiments were conducted to obtain new data about ideal amino acid ratio (IAAR) between branched-chain amino acids (BCAA) leucine (Leu), isoleucine (Ile), valine (Val) and lysine (Lys) in meat type chicken diets.

Branched-chain α-keto acids in plasma of growing chicken: when is the time for blood sampling?

Complementary to quantitative requirement studies for the branched-chain amino acids (BCAA) leucine, isoleucine and valine, studies on dynamics of α-keto acids yielded by degradation of the BCAA could provide important additional metabolic insights. Generally, the first step in catabolism of the BCAAs is undertaken by the same enzyme (branched-chain amino acid transferase; Harper et al., 1984) and yields the corresponding branched-chain α-keto acids (BCKA): α-ketoisocaproic acid (KIC), α-ketomethylvaleric acid (KMV) and α-ketoisovaleric acid (KIV), for leucine, isoleucine and valine, respectively. In human beings, a deficiency of this enzyme may create a buildup of the BCAA and their corresponding BCKA, leading to the maple syrup urine disease (Langenbeck et al., 1978). Therefore, determination of the BCKA concentration in blood plasma is a standard procedure in humans. However, for growing chicken, guidelines are not available to indicate the optimal time schedule for sampling. The current study was conducted both to establish a method to detect BCKA in chicken plasma and to yield information about the time course of BCKA in blood from the jugular vein for an improved understanding of the BCAA metabolism in growing chicken.