The protein requirement for maintenance in the White-crowned Sparrow, Zonotrichia leucophrys gambelii

1993 ◽  
Vol 71 (10) ◽  
pp. 2111-2120 ◽  
Author(s):  
Mary E. Murphy
Keyword(s):  
Amino Acid ◽  
Body Mass ◽  
Dietary Protein ◽  
Wild Birds ◽  
N Balance ◽  
N Loss ◽  
Protein Requirement ◽  
Zonotrichia Leucophrys ◽  
Protein Requirements ◽  
Zonotrichia Leucophrys Gambelii

Assumptions about potential mismatches between protein demand and protein availability are implicit in many hypotheses pertaining to the ecology of wild birds. However, few direct measures of the protein requirements of wild birds have been made. I evaluated the requirement for protein for maintenance of a wild granivorous passerine, the White-crowned Sparrow (Zonotrichia leucophrys gambelii). I estimated protein requirement from measures of endogenous nitrogen (N) loss, N balance, and changes in body mass in wintering adult birds. The experimental birds were kept indoors at 23 °C (8.5 h light: 15.5 h dark) and fed semisynthetic diets that differed only in their concentrations of protein (0–17.3%) and starch, which were reciprocally adjusted. The amino acid profiles of the protein in the diets were identical and were formulated to match the average amino acid profile of the mixed proteins of a diet containing grains, seeds, insects, and fruits. In White-crowned Sparrows, the protein requirements for maintenance of body mass (366 mg/d) and a positive N balance equal to that of birds ingesting the acclimation diets (436 mg/d) were 7.3 and 8.7% protein, respectively, in a diet containing 12.4 kJ apparent metabolizable energy per gram dry mass. The estimated minimum maintenance requirement for protein for N equilibrium, derived from regressing N excretion on N intake, equalled 264 mg protein/d, or ca. 5.3% dietary protein. Measures of endogenous N loss (endogenous urinary N loss plus metabolic fecal N loss) equalled 14.7 mg N/d, indicating that White-crowned Sparrows need to replace at least 92 mg body protein/d. Dietary protein content had little influence on the birds' utilization of dietary energy and daily metabolized energy. The apparent contradiction in the requirement for a positive N balance to maintain body mass is discussed.

scholarly journals Indicator amino acid oxidation protein requirement estimate in endurance-trained men 24 h postexercise exceeds both the EAR and current athlete guidelines

2019 ◽  
Vol 316 (5) ◽  
pp. E741-E748 ◽  
Author(s):  
Arash Bandegan ◽  
Glenda Courtney-Martin ◽  
Mahroukh Rafii ◽  
Paul B. Pencharz ◽  
Peter W. R. Lemon
Keyword(s):  
Amino Acid ◽  
Dietary Protein ◽  
Protein Pattern ◽  
Training Session ◽  
Acid Mixture ◽  
Acid Oxidation ◽  
Institute Of Medicine ◽  
Protein Requirement ◽  
Amino Acid Oxidation ◽  
Protein Requirements

Despite studies indicating increased protein requirements in strength-trained or endurance-trained (ET) individuals, the Institute of Medicine has concluded that “no additional dietary protein is suggested for healthy adults undertaking resistance or endurance exercise,” and the controversy regarding exercise effects on protein requirements continues. The objective of this study was to determine the dietary protein requirement of healthy young ET men (≥1 yr training experience) 24 h post exercise (to minimize any acute effects of the previous training session) by measuring the oxidation of ingested l-[1-13C]phenylalanine to 13CO2 in response to graded intakes of protein (indicator amino acid oxidation technique). Eight men [maximal oxygen consumption 64.1 ml·kg−1·min−1 (SD 3.7)] were each studied 24 h postexercise repeatedly with protein intakes ranging from 0.3 to 3.5 g·kg−1·day−1. Protein was fed as an amino acid mixture based on the protein pattern in egg, except for phenylalanine and tyrosine, which were maintained at constant amounts across all protein intakes. For 2 days before the study day, all participants consumed 1.6 g protein·kg−1·day−1. The estimated average requirement (EAR) for protein was determined by applying a nonlinear mixed-effects change-point regression analysis to F13CO2 (label tracer oxidation in 13CO2 breath), which identified a breakpoint in the F13CO2 in response to the graded amounts of protein. The EAR for protein and the upper 95% confidence interval were 2.1 and 2.6 g·kg−1·day−1, respectively. These data suggest that the protein EAR for ET men 24 h postexercise exceeds the Institute of Medicine EAR and established athlete guidelines by ~3.5- and 1.3-fold, respectively.

Protein intake and the dynamics of the postnuptial molt in White-crowned Sparrows, Zonotrichia leucophrys gambelii

1991 ◽  
Vol 69 (8) ◽  
pp. 2225-2229 ◽  
Author(s):  
Mary E. Murphy ◽  
James R. King
Keyword(s):  
Body Mass ◽  
Sulfur Amino Acids ◽  
Daily Consumption ◽  
Free Living ◽  
Zonotrichia Leucophrys ◽  
High Quality Protein ◽  
Protein Group ◽  
The Mean ◽  
Zonotrichia Leucophrys Gambelii

Nutritional constraints have often been invoked as either ultimate or proximate agents that account for variation in the schedule and intensity of molt and the quality of the new plumage. We examined this hypothesis by analyzing the dynamics of postnuptial molt and the condition of the new feathers in seven groups of White-crowned Sparrows (Zonotrichia leucophrys gambelii) in which the mean daily consumption of high-quality protein in otherwise balanced diets ranged from subadequate (0.20 g/bird) to superadequate (3.23 g/bird). Mean body mass during molt did not differ among the six groups consuming 0.46 g/bird-day or more (0.69, 0.97, 1.76, 1.99, and 3.23 g/bird-day) but was significantly less throughout molt (e.g., ca. 20 vs. 26 g in mid to late molt) in the group subsisting on 0.20 g/bird-day. The mean date of molt onset (27 June – 2 July) was statistically the same in all the groups, as was the duration of molt (51–57 days) in the six groups consuming 0.46 g or more of protein per day. In the lowest-protein group (0.20 g/bird-day) the molt lasted > 111 days. The protraction of molt resulted from both a slower growth rate of flight feathers and longer shedding intervals between them. The new primary remiges of the birds in this group averaged 4–9% shorter than in the six other groups, which were statistically indistinguishable from each other. These results are consistent with those of earlier experiments on the effects on molt of shortages of nutritionally balanced diets and of diets deficient only in sulfur amino acids. Molt is very resistant to the kinds of malnutrition that free-living birds may encounter. Only very severe levels of privation that sharply depress body mass and potentially threaten life significantly slow the rate of molt or reduce the quality of plumage.

scholarly journals Protein requirements in tropical countries: nitrogen losses in sweat and their relation to nitrogen balance

1967 ◽  
Vol 21 (4) ◽  
pp. 833-843 ◽  
Author(s):  
Ann Ashworth ◽  
A. D. B. Harrower
Keyword(s):  
Initial Period ◽  
Tropical Climate ◽  
The Body ◽  
N Balance ◽  
Nitrogen Losses ◽  
Whole Body ◽  
Physical Work ◽  
N Loss ◽  
Total N ◽  
Protein Requirements

1. An experiment was undertaken to determine whether high rates of sweating in a tropical climate affect protein requirements by increasing the total nitrogen losses from the body.2. Six fully acclimatized volunteers were given a diet supplying 50 g protein (= 8 g N) daily. They performed strenuous physical work of a normal nature for an average of 6½ h a day for two 5-day periods. During control periods the subjects took minimal exercise and lived in a cool environment. N balance was measured throughout.3. Rates of sweating were measured by weighing. Whole body sweat was collected and the concentrations were measured of nitrogen, sodium and potassium. During 6½ h work approximately 3 l. of sweat were lost, containing on average 0·49 g N, 64 m-equiv. Na and 22 m-equiv. K.4. The N concentration in sweat was 0·20 mg/g, which is lower than that found by most other workers. It is suggested that acclimatization is an important factor in reducing N loss by sweating.5. There was a marked decrease in urinary Na excretion during sweating, which compensated fully for the loss of Na in sweat. Renal compensation for loss of K was less efficient.6. Because the total N loss in sweat was small, it was not possible to establish with certainty whether it was compensated for by a reduced renal excretion of N. However, after the initial period the subjects were in N balance in spite of the relatively low protein intake.7. It is concluded that there is no evidence to suggest that heavy sweating under natural conditions in a tropical climate causes a significant increase in protein requirements.

scholarly journals A Comparison of Dietary Protein Digestibility, Based on DIAAS Scoring, in Vegetarian and Non-Vegetarian Athletes

Nutrients ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 3016 ◽  
Author(s):  
Corinne Ciuris ◽  
Heidi M. Lynch ◽  
Christopher Wharton ◽  
Carol S. Johnston
Keyword(s):  
Amino Acid ◽  
G Protein ◽  
Lean Body Mass ◽  
Body Mass ◽  
Dietary Protein ◽  
Protein Quality ◽  
Peak Torque ◽  
Diet Group ◽  
Leg Extension ◽  
Vegetarian Diets

Vegetarian diets provide an abundance of nutrients when carefully planned. However, vegetarian diets may have lower protein quality compared to omnivorous diets, a reflection of less favorable amino acid profiles and bioavailability. Hence, the current recommended dietary allowance for protein may not be adequate for some vegetarian populations. The purpose of this study was to determine dietary protein quality using the DIAAS (Digestible Indispensable Amino Acid Score) method in vegetarian and omnivore endurance athletes. DIAAS scores reflect the true ileal digestibility of the indispensable amino acids that are present in food items, and these scores can be used to compute the available protein in diet plans. Thirty-eight omnivores and 22 vegetarians submitted seven-day food records that were analyzed for nutrient content, and DIAAS scores were computed by diet group. Average available protein (g) was compared along with participants’ lean body mass and strength (quantified using the peak torque of leg extension). DIAAS scores and available protein were higher for omnivorous versus vegetarian athletes (+11% and +43%, respectively, p < 0.05). Omnivorous participants had significantly higher lean body mass than vegetarian participants (+14%), and significant correlations existed between available protein and strength (r = 0.314) and available protein and lean body mass (r = 0.541). Based upon available protein, as determined through the DIAAS, vegetarian athletes in this study would need to consume, on average, an additional 10 g protein daily to reach the recommended intake for protein (1.2 g/kg/d). An additional 22 g protein daily would be needed to achieve an intake of 1.4 g/kg/d, the upper end of the recommended intake range.

Adaptation to Low Protein and Energy Intakes

1989 ◽  
Vol 48 (1) ◽  
pp. 20-30 ◽  
Author(s):  
Nevin Scrimshaw ◽  
Vernon Young
Keyword(s):  
Physical Activity ◽  
Amino Acid ◽  
Lean Body Mass ◽  
Body Mass ◽  
Dietary Protein ◽  
Economic Consequences ◽  
Low Protein ◽  
Lower Protein ◽  
Reduced Physical Activity ◽  
Body Energy

This paper focuses on two principal issues. First, what are the consequences of low dietary protein and amino acid intakes? Second, what are the physiological and social limits to restricted energy intakes? The concepts of adaptation and accommodation are presented. It is suggested that the limit of adaptation to low dietary protein is achieved at the intake level considered minimally necessary to maintain health in well-nourished subjects, as judged by nitrogen balance, stable lean body mass and absence of functional impairment. For lower protein intakes survival is prolonged via an accommodation, involving loss of lean body mass and reduced rates of protein and amino acid turnover. There is only a limited metabolic capacity for adaptation to reduced energy intakes, but variations in the level and pattern of physical activity permit a maintenance of body energy balance over a broad range of energy intakes. Where reduced physical activity to balance restricted energy intakes has adverse social, cultural and/or economic consequences the response should be viewed as an accommodation and not as adaptation. The range of adaptation depends on the criteria of normality and the assessment of the biological and social costs of changes with low intakes.

scholarly journals Dietary Protein Requirement of Men >65 Years Old Determined by the Indicator Amino Acid Oxidation Technique Is Higher than the Current Estimated Average Requirement

2015 ◽  
Vol 146 (4) ◽  
pp. 681-687 ◽  
Author(s):  
Mahroukh Rafii ◽  
Karen Chapman ◽  
Rajavel Elango ◽  
Wayne W Campbell ◽  
Ronald O Ball ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dietary Protein ◽  
Acid Oxidation ◽  
Protein Requirement ◽  
Amino Acid Oxidation

A note on the protein requirement for maintenance of adult rams

1970 ◽  
Vol 12 (1) ◽  
pp. 185-189 ◽  
Author(s):  
Manohar Singh ◽  
V. Mahadevan
Keyword(s):  
Crude Protein ◽  
Dry Matter ◽  
Latin Square ◽  
N Balance ◽  
Protein Requirement ◽  
Protein Requirements ◽  
Factorial Method ◽  
Utilization Of Protein ◽  
True Digestibility ◽  
Digestible Crude Protein

SUMMARYNitrogen balance studies of latin square design were conducted on six adult rams receiving diets with approximately 4, 8 and 16% crude protein. The diets were almost isocaloric and contained groundnut cake, wheat bran, maize starch, and chopped wheat straw. Metabolic faecal and endogenous urinary N were 0·24 ± 0·003 g/100 g dry-matter intake and 0·038 ± 0·01 g/kg body weight per day. Biological value, true digestibility and coefficient of net utilization were 86·9 ± 8·68, 93·4 ± 1·94 and 79·6 ± 2·47, respectively.Daily digestible crude protein requirements for maintenance estimated by the factorial method (0·875 + 0·;06 g/kg W0·734) and from N balance and the net utilization of protein (0·893 + 0·03 g/kg W0·734) were similar but slightly higher than the requirement estimated from N balance alone (0·738 ± 0·04 g/kg W0·734). All values are lower than the conventional recommendations.

scholarly journals Dietary Protein Requirement of Female Adults >65 Years Determined by the Indicator Amino Acid Oxidation Technique Is Higher Than Current Recommendations

2014 ◽  
Vol 145 (1) ◽  
pp. 18-24 ◽  
Author(s):  
Mahroukh Rafii ◽  
Karen Chapman ◽  
Jillian Owens ◽  
Rajavel Elango ◽  
Wayne W Campbell ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dietary Protein ◽  
Acid Oxidation ◽  
Protein Requirement ◽  
Amino Acid Oxidation

scholarly journals Gonadotropin-inhibitory hormone in Gambel's white-crowned sparrow (Zonotrichia leucophrys gambelii): cDNA identification, transcript localization and functional effects in laboratory and field experiments

2004 ◽  
Vol 182 (1) ◽  
pp. 33-42 ◽  
Author(s):  
T Osugi ◽  
K Ukena ◽  
GE Bentley ◽  
S O'Brien ◽  
IT Moore ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cellular Localization ◽  
Field Experiments ◽  
Bird Species ◽  
Free Living ◽  
Zonotrichia Leucophrys ◽  
Gonadotropin Release ◽  
Zonotrichia Leucophrys Gambelii ◽  
Gonadotropin Inhibitory Hormone ◽  
Seasonally Breeding

The neuropeptide control of gonadotropin secretion is primarily through the stimulatory action of the hypothalamic decapeptide, GnRH. We recently identified a novel hypothalamic dodecapeptide with a C-terminal LeuPro-Leu-Arg-Phe-NH2 sequence in the domestic bird, Japanese quail (Coturnix japonica). This novel peptide inhibited gonadotropin release in vitro from the quail anterior pituitary; thus it was named gonadotropin-inhibitory hormone (GnIH). GnIH may be an important factor regulating reproductive activity not only in domesticated birds but also in wild, seasonally breeding birds. Thus, we tested synthetic quail GnIH in seasonally breeding wild bird species. In an in vivo experiment, chicken gonadotropin-releasing hormone-I (cGnRH-I) alone or a cGnRH-I/quail GnIH cocktail was injected i.v. into non-breeding song sparrows (Melospiza melodia). Quail GnIH rapidly (within 2 min) attenuated the GnRH-induced rise in plasma LH. Furthermore, we tested the effects of quail GnIH in castrated, photostimulated Gambel's white-crowned sparrows (Zonotrichia leucophrys gambelii), using quail GnIH or saline for injection. Again, quail GnIH rapidly reduced plasma LH (within 3 min) compared with controls. To characterize fully the action of GnIH in wild birds, the identification of their endogenous GnIH is essential. Therefore, in the present study a cDNA encoding GnIH in the brain of Gambel's white-crowned sparrow was cloned by a combination of 3' and 5' rapid amplification of cDNA ends and compared with the quail GnIH cDNA previously identified. The deduced sparrow GnIH precursor consisted of 173 amino acid residues, encoding one sparrow GnIH and two sparrow GnIH-related peptides (sparrow GnIH-RP-1 and GnIH-RP-2) that included Leu-Pro-Xaa-Arg-Phe-NH2 (Xaa=Leu or Gln) at their C-termini. All these peptide sequences were flanked by a glycine C-terminal amidation signal and a single basic amino acid on each end as an endoproteolytic site. Although the homology of sparrow and quail GnIH precursors was approximately 66%, the C-terminal structures of GnIH, GnIH-RP-1 and GnIH-RP-2 were all identical in two species. In situ hybridization revealed the cellular localization of sparrow GnIH mRNA in the paraventricular nucleus (PVN) of the hypothalamus. Immunohistochemical analysis also showed that sparrow GnIH-like immunoreactive cell bodies and terminals were localized in the PVN and median eminence respectively. Thus, only the sparrow PVN expresses GnIH, which appears to be a hypothalamic inhibitory factor for LH release, as evident from our field injections of GnIH into free-living breeding white-crowned sparrows. Sparrow GnIH rapidly (within 2 min) reduced plasma LH when injected into free-living Gambel's white-crowned sparrows on their breeding grounds in northern Alaska. Taken together, our results indicate that, despite amino acid sequence differences, quail GnIH and sparrow GnIH have similar inhibitory effects on the reproductive axis in wild sparrow species. Thus, GnIH appears to be a modulator of gonadotropin release.

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