The effects of amino acid loading on glomerular filtration in dogs on different protein diets: a controlled study

1988 ◽  
Vol 66 (7) ◽  
pp. 993-996
Author(s):  
A. Fine

Considerable variation in both the magnitude and pattern of response of glomerular filtration rate (GFR) to protein loading in omnivores has been reported in the literature. These experiments were designed to examine, under carefully controlled conditions, the effects of different acute protein loads given to a group of dogs placed on a normal protein (NP) intake for 4 weeks and to the same dogs when on a low protein (LP) intake for the same duration. GFR did not change when the dogs were changed from NP to LP diets, 3.0 + 0.2 (NP) vs. 3.2 + 0.3 (LP) mL∙min−1∙kg−1. Intravenous amino acid was infused at 15, 25, and 40 mL/h on different days. Regardless of whether on a low or high protein diet, the GFR did not change. Another set of experiments was performed in another Canadian centre 2000 miles away. In these studies with dogs on a similar normal protein diet, a striking rise in GFR occurred following amino-acid infusion at 25 mL/h, 3.1 + 0.3 vs. 4.8 + 0.6 mL∙min−1∙kg−1 (p < 0.001). These results demonstrate, at least in the dog, that contrary to previous reports, dietary protein changes do not affect the GFR. Furthermore, the GFR response to an acute intravenous protein load does not depend on the amount of protein given nor the previous protein diet but appears to be possibly dependent on other factors that may be environmental or congenital.

1986 ◽  
Vol 251 (1) ◽  
pp. F132-F140 ◽  
Author(s):  
P. Castellino ◽  
B. Coda ◽  
R. A. DeFronzo

The effect of amino acid (AA) infusion on renal hemodynamics was examined in 19 healthy subjects. Thirteen subjects participated in the first protocol (normal protein intake) and six in the second protocol (low protein intake). The first protocol consisted of three studies: study 1 (n = 13), AA were infused over 3 h to increase plasma amino acid levels two- to threefold; study 2 (n = 7), AA were infused with somatostatin and peripheral replacement of insulin, glucagon, and growth hormone; study 3 (n = 6), somatostatin was infused with basal hormonal replacement as in study 2. During study 1, glomerular filtration rate (GFR) rose by 20% (from 107 +/- 5 to 128 +/- 4 ml . 1.73 m-2 . min-1, P less than 0.001). Renal plasma flow (RPF) increased by a similar percentage (599 +/- 35 to 704 +/- 33 ml . 1.73 m-2 . min-1, P less than 0.001). When somatostatin was infused with AA (study 2), neither GFR nor RPF changed from base line. Somatostatin infusion alone (study 3) had no effect on GFR or RPF. During protocol 2, six subjects received a low-protein diet (40 g/day) for 7 days and AA were infused as per study 1. Base-line GFR (104 +/- 5 to 96 +/- 4 ml . 1.73 m-2 . min-1 and RPF (593 +/- 32 to 507 +/- 23 ml . 1.73 m-2 . min-1) both decreased (P less than 0.02) after the low-protein diet.(ABSTRACT TRUNCATED AT 250 WORDS)


2006 ◽  
Vol 6 (1) ◽  
pp. 47-59
Author(s):  
Nancy Montilla ◽  
◽  
Lolito Bestil ◽  
Sulpecio Bantugan ◽  

A feeding trial with broilers was conducted to evaluate the effects of amino acids (lysine and methionine) supplementation of diets low in protein content on the voluntary intake, feed conversion efficiency, broiler performance, and cost and return of broiler production. Results showed cumulative voluntary feed intake was not significantly affected by lowering the protein content of the diet. Cumulative weight gain of broilers was lower with diet when supplemented iwht lysine and methionine to meet requirements. Birds fed with diets low in protein has less efficient feed converstion, but became comparable with those receiveing diets high in protein when supplemented with amino acids. Feed cost per kilogram broiler produced was not significantly affected by diets used in the study, although the low-protien diet with amino acid supplement had the lowest values. In terms of return above feed and chick cost, broilers fed with high-protein diet had the greatest value, but not significantly different from birds fed with low-protien diet with amino acid supplementation which gave about P10 per bird higher returns than those fed low-protein diet without amino acid supplementation.


1972 ◽  
Vol 23 (5) ◽  
pp. 859 ◽  
Author(s):  
GJ Faichney

The effect of formaldehyde treatment of peanut meal on the digestion of barley-peanut meal diets was studied in fistulated crossbred sheep at two peanut meal and therefore dietary protein levels. There were no differences either between protein levels or due to treatment in the overall digestion of organic matter, but more of this digestion took place in the stomach when the low protein diets were given. Dietary starch was completely digested. There was no effect of protein level or of formaldehyde treatment on the partition of starch digestion between the stomach and the intestines. About 10% of the dietary nitrogen disappeared from the stomach when the high protein diet containing untreated peanut meal was given; treatment resulted in a small net gain of nitrogen in the stomach. There was a net gain of nitrogen in the stomach when the low protein diets were given, the gain tending to be greater when the peanut meal was treated. When the meal was treated, there was a small but not significant increase (c. 2%) for the low protein diet and a substantial increase (c. 31 %) for the high protein diet in the amount of crude protein digested in the intestines per unit of digestible organic matter intake. Changes observed in the composition and flow of digesta and in plasma urea and cc-amino nitrogen levels are discussed in relation to the digestion of organic matter and protein.


2021 ◽  
Vol 12 ◽  
Author(s):  
Xin Tao ◽  
Bo Deng ◽  
Qizhi Yuan ◽  
Xiaoming Men ◽  
Jie Wu ◽  
...  

Low protein diets are commonly used in the growing-finishing pig stage of swine production; however, the effects of low dietary protein on the intestinal microbiota and their metabolites, and their association with pig sex, remain unclear. The present study aimed to assess the impact of a low crude protein (CP) diet on the gut microbiome and metabolome, and to reveal any relationship with sex. Barrows and gilts (both n = 24; initial body = 68.33 ± 0.881 kg) were allocated into two treatments according to sex. The four groups comprised two pairs of gilts and barrows fed with a high protein diet (CP 17% at stage I; CP 13% at stage II) and a low protein diet (CP 15% at stage I; CP 11% at stage II), respectively, for 51 d. Eight pigs in each group were slaughtered and their colon contents were collected. Intestinal microbiota and their metabolites were assessed using 16S rRNA sequencing and tandem mass spectrometry, respectively. The low protein diet increased intestinal microbiota species and richness indices (P &lt; 0.05) in both sexes compared with the high protein diet. The sample Shannon index was different (P &lt; 0.01) between barrows and gilts. At the genus level, unidentified Clostridiales (P &lt; 0.05), Neisseria (P &lt; 0.05), unidentified Prevotellaceae (P &lt; 0.01) and Gracilibacteria (P &lt; 0.05) were affected by dietary protein levels. The relative abundance of unidentified Prevotellaceae was different (P &lt; 0.01) between barrows and gilts. The influence of dietary protein levels on Neisseria (P &lt; 0.05), unidentified Prevotellaceae (P &lt; 0.01) and Gracilibacteria (P &lt; 0.05) were associated with sex. Metabolomic profiling indicated that dietary protein levels mainly affected intestinal metabolites in gilts rather than barrows. A total of 434 differentially abundant metabolites were identified in gilts fed the two protein diets. Correlation analysis identified that six differentially abundant microbiota communities were closely associated with twelve metabolites that were enriched for amino acids, inflammation, immune, and disease-related metabolic pathways. These results suggested that decreasing dietary protein contents changed the intestinal microbiota in growing-finishing pigs, which selectively affected the intestinal metabolite profiles in gilts.


2001 ◽  
Vol 52 (7) ◽  
pp. 791
Author(s):  
L. Ma ◽  
F. R. Dunshea ◽  
Y. M. Brockwell ◽  
R. L. Inglis ◽  
D. J. Kingston ◽  
...  

Plasma hormone concentrations were measured in gilts after fasting, long-term protein restriction, or supplementation. In 11-week-old pigs fasted overnight, plasma insulin, glucagon, gastrin, urea, and glucose were increased 30 min after re-feeding (P < 0.05), whereas IGF-I did not change. In 16-week-old gilts fed a standard commercial diet [14.6% crude protein (CP)], or a high-protein diet (16.7% CP) for 4 weeks, the high-protein diet increased weight gain (13%; P < 0.05) and carcass weight (4%; P < 0.05), but did not alter plasma IGF-I, insulin, or glucagon. In 10-week-old gilts fed high-protein diets (19.4% and 18.3% CP), or low-protein diets (15.5% and 13.3% CP) for 12 weeks during the grower and finisher phases, respectively, the low-protein diet decreased weight gain (18%; P < 0.001) and carcass weight (11%; P < 0.01), with a marked increase in plasma glucagon (P < 0.05), no change in insulin, and only a trend towards decreased IGF-I (P = 0.1). The pigs were more sensitive to altered dietary protein at 10 weeks of age than at 16 weeks. Plasma IGF-I was not responsive to the short-term effects of feeding or the long-term effects of dietary protein. Glucagon could provide a useful marker for nutritional status in young pigs, provided that time of feeding is taken into account.


2000 ◽  
Vol 134 (1) ◽  
pp. 89-99 ◽  
Author(s):  
N. L. BUTTER ◽  
J. M. DAWSON ◽  
D. WAKELIN ◽  
P. J. BUTTERY

The aim of this study was to determine whether the inclusion of a condensed tannin (quebracho tannin, QT) and/or the elevation of dietary protein could reduce Trichostrongylus colubriformis establishment and existence in the small intestine of lambs. Thirty-six lambs (mean liveweight 32·6±3·9 kg) were randomly allocated to one of six experimental groups, groups 1–5 were parasitized with a trickle infection of 3000 infective Trichostrongylus colubriformis larvae daily, whilst group 6 remained as uninfected controls. Experimental diets were formulated to contain 222 g CP/kg (high protein) or 97 g CP/kg (low protein) with or without the inclusion of 50 g QT/kg. All six animal groups were fed the low protein diet, group 2 fed low protein diet+QT, for one month prior to infection (groups 1–5). Once nematode eggs were observed in the faeces, diets were abruptly changed in three experimental groups. Group 1 remained on the low protein diet, group 2 remained on the low protein+QT diet, group 3 changed to the high protein diet, group 4 changed to the high protein+QT diet, group 5 changed to the low protein+QT diet and group 6 remained uninfected and fed the low protein diet. Production, haematological and parasitological parameters were monitored at regular intervals. Results show that parasitized animals fed the high protein diet achieved growth rates similar to those of uninfected low protein-fed lambs. Inclusion of dietary QT did not depress liveweight gain. Total daily faecal egg counts declined after feeding the high protein diet. Inclusion of QT into the low protein diet also reduced faecal egg counts to similar levels observed in the high protein-fed lambs. The inclusion of QT into the high protein diet did not further reduce faecal egg counts. No significant differences in the haematological parameters measured were observed between infected animals (groups 1–5), suggesting that the beneficial effect of dietary QT in the low protein diet is unlikely to be mediated through an immune response. These data suggest that the inclusion of QT in low protein diets may be an alternative to feeding high protein diets to reduce nematode burden in lambs.


1941 ◽  
Vol 74 (6) ◽  
pp. 591-600 ◽  
Author(s):  
H. Philipsborn ◽  
L. N. Katz ◽  
S. Rodbard

The effect of high and low protein diets were studied on fourteen dogs in twenty-four different experiments. In only two of these animals, both with moderate renal excretory failure, was a reversible rise in blood pressure elicited by a high protein diet. The possible mechanisms involved in meeting an increased excretory load are discussed.


2001 ◽  
Vol 52 (5) ◽  
pp. 603
Author(s):  
L. Ma ◽  
F. R. Dunshea ◽  
Y. M. Brockwell ◽  
R. L. Inglis ◽  
D. J. Kingston ◽  
...  

Plasma hormone concentrations were measured in gilts after fasting, long-term protein restriction, or supplementation. In 11-week-old pigs fasted overnight, plasma insulin, glucagon, gastrin, urea, and glucose were increased 30 min after re-feeding (P < 0.05), whereas IGF-I did not change. In 16-week-old gilts fed a standard commercial diet [14.6% crude protein (CP)], or a high-protein diet (16.7% CP) for 4 weeks, the high-protein diet increased weight gain (13%; P < 0.05) and carcass weight (4%; P < 0.05), but did not alter plasma IGF-I, insulin, or glucagon. In 10-week-old gilts fed high-protein diets (19.4% and 18.3% CP), or low-protein diets (15.5% and 13.3% CP) for 12 weeks during the grower and finisher phases, respectively, the low-protein diet decreased weight gain (18%; P < 0.001) and carcass weight (11%; P < 0.01), with a marked increase in plasma glucagon (P < 0.05), no change in insulin, and only a trend towards decreased IGF-I (P = 0.1). The pigs were more sensitive to altered dietary protein at 10 weeks of age than at 16 weeks. Plasma IGF-I was not responsive to the short-term effects of feeding or the long-term effects of dietary protein. Glucagon could provide a useful marker for nutritional status in young pigs, provided that time of feeding is taken into account.


1996 ◽  
Vol 1996 ◽  
pp. 87-87
Author(s):  
L A Crompton ◽  
M A Lomax ◽  
C K Reynolds ◽  
F R C Backwell ◽  
B J Bequette ◽  
...  

Milk protein concentration can be influenced by dietary manipulation, but the efficiency of amino acid transfer into milk and the predictability of the response are both poor. Previous reports from this research group have demonstrated that milk protein concentration can be repeatedly increased in response to vascular infusions of essential amino acids (EAA) in animals fed on a low crude protein (CP) diet (140 g CP/kg DM) in mid-lactation (Metcalf et al., 1996). The present study was designed to compare milk protein content responses to vascular EAA infusion in animals fed a high protein diet (180 g CP/kg DM) at peak lactation.


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