50 research outputs found
Relevance of dietary protein concentration and quality as risk factors for the formation of calcium oxalate stones in cats
The role of dietary protein for the development of feline calcium oxalate
(CaOx) uroliths has not been conclusively clarified. The present study
evaluated the effects of a varying dietary protein concentration and quality
on critical indices for the formation of CaOx uroliths. Three diets with a
high protein quality (10–11 % greaves meal/diet) and a varying crude protein
(CP) concentration (35, 44 and 57 % in DM) were compared. Additionally, the 57
% CP diet was compared with a fourth diet that had a similar CP concentration
(55 % in DM), but a lower protein quality (34 % greaves meal/diet). The Ca and
oxalate (Ox) concentrations were similar in all diets. A group of eight cats
received the same diet at the same time. Each feeding period was divided into
a 21 d adaptation period and a 7 d sampling period to collect urine. There
were increases in urinary volume, urinary Ca concentrations, renal Ca and Ox
excretion and urinary relative supersaturation (RSS) with CaOx with increasing
dietary protein concentrations. Urinary pH ranged between 6·34 and 6·66 among
all groups, with no unidirectional effect of dietary protein. Lower renal Ca
excretion was observed when feeding the diet with the lower protein quality,
however, the underlying mechanism needs further evaluation. In conclusion,
although the observed higher urinary volume is beneficial, the increase in
urinary Ca concentrations, renal Ca and Ox excretion and urinary RSS CaOx
associated with a high-protein diet may be critical for the development of
CaOx uroliths in cats
Seed Mucilage Improves Seedling Emergence of a Sand Desert Shrub
The success of seedling establishment of desert plants is determined by seedling emergence response to an unpredictable precipitation regime. Sand burial is a crucial and frequent environmental stress that impacts seedling establishment on sand dunes. However, little is known about the ecological role of seed mucilage in seedling emergence in arid sandy environments. We hypothesized that seed mucilage enhances seedling emergence in a low precipitation regime and under conditions of sand burial. In a greenhouse experiment, two types of Artemisia sphaerocephala achenes (intact and demucilaged) were exposed to different combinations of burial depth (0, 5, 10, 20, 40 and 60 mm) and irrigation regimes (low, medium and high, which simulated the precipitation amount and frequency in May, June and July in the natural habitat, respectively). Seedling emergence increased with increasing irrigation. It was highest at 5 mm sand burial depth and ceased at burial depths greater than 20 mm in all irrigation regimes. Mucilage significantly enhanced seedling emergence at 0, 5 and 10 mm burial depths in low irrigation, at 0 and 5 mm burial depths in medium irrigation and at 0 and 10 mm burial depths in high irrigation. Seed mucilage also reduced seedling mortality at the shallow sand burial depths. Moreover, mucilage significantly affected seedling emergence time and quiescence and dormancy percentages. Our findings suggest that seed mucilage plays an ecologically important role in successful seedling establishment of A. sphaerocephala by improving seedling emergence and reducing seedling mortality in stressful habitats of the sandy desert environment
Effects of variations in sodium and crude protein concentrations as well as protein quality in a diet on urine composition of healthy cats
Ziel dieser Arbeit war es, die Auswirkungen des Natrium- und Rohproteingehalts
sowie der Proteinqualität im Futter auf die Harneigenschaften von Katzen zu
untersuchen und mögliche Risikofaktoren einer Kalziumoxalatsteinentstehung zu
ermitteln. Hierzu wurden insgesamt 7 Diäten mit variierenden Gehalten an
Natrium (0,38 %, 0,65 %, 1,14 % und 1,43 %), Rohprotein (34,7 %, 43,8 % und
57,4 %) und Griebenmehl (12 % und 35 %) in jeweils dreiwöchigen Adaptations-
und einwöchigen Bilanzperioden an 8 gesunde Katzen verfüttert. In den
Bilanzperioden wurden die Katzen einzeln in Stoffwechselkäfigen gehalten, um
den Harn und Kot der Tiere quantitativ zu sammeln. Zudem wurde die tägliche
Futter- und Wasseraufnahme der Katzen ermittelt. Im Harn wurden die
Konzentrationen an Anionen und Kationen sowie der pH-Wert gemessen. Anhand
dieser Daten konnte zudem die relative Übersättigung des Harns mit
Kalziumoxalat und Struvit rechnerisch ermittelt werden. In den Kotproben
wurden die Trockensubstanzgehalte sowie die Konzentrationen an Rohnährstoffen
und Mineralstoffen bestimmt. Die wichtigsten Ergebnisse der vorliegenden
Untersuchungen sollen nachfolgend kurz dargestellt werden. Mit steigenden
Natriumgehalten im Futter konnte ein erhöhtes Harnvolumen sowie eine
verstärkte renale Ausscheidung von Natrium bei den Katzen beobachtet werden.
Die Kalziumkonzentration im Harn wurde nicht beeinflusst, jedoch stieg die
renale Ausscheidung von Kalzium mit zunehmendem Natriumgehalt in der Ration
von 0,62 auf 1,05 mg/kg Körpermasse/Tag an. Die Konzentrationen an Oxalat,
Zitrat, Phosphor und Kalium im Harn nahmen hingegen mit steigendem
Natriumgehalt in den Diäten ab. Die pH-Werte des Harns lagen bei Einsatz der
Versuchsdiäten zwischen 6,33 und 6,45 (P > 0,05). Der Natriumgehalt im Futter
hatte keinen Einfluss auf die relative Übersättigung des Harns mit
Kalziumoxalat. Somit konnte dieser Studienteil einige vorteilhafte
Auswirkungen einer kurzzeitigen hohen Natriumaufnahme bei Katzen vor dem
Hintergrund der Kalziumoxalatsteinentstehung aufzeigen. Insbesondere die
Tatsache, dass die Kalziumkonzentrationen im Harn sowie die relative
Übersättigung des Harns mit Kalziumoxalat unverändert und die
Oxalatkonzentrationen im Harn reduziert waren, könnte zur Prävention von
Kalziumoxalatsteinen beitragen. Mit zunehmendem Rohproteingehalt im Futter
konnte ein Anstieg des Harnvolumens, der Kalziumkonzentrationen im Harn, der
renalen Kalzium- und Oxalatausscheidung sowie der relativen Übersättigung des
Harns mit Kalziumoxalat festgestellt werden. Der pH-Wert des Harns lag bei
allen Gruppen zwischen 6,34 und 6,66, wobei kein unidirektionaler Einfluss des
Rohproteingehalts im Futter beobachtet werden konnte (P > 0,05). Mit Ausnahme
des gesteigerten Harnvolumens sind diese Effekte einer proteinreichen
FĂĽtterung fĂĽr die Prophylaxe von Kalziumoxalatharnsteinen bei Katzen insgesamt
als kritisch zu bewerten. Bei Fütterung der Diät mit dem höheren Anteil an
Griebenmehl konnte eine geringere renale Kalziumausscheidung bei den Katzen
nachgewiesen werden. Die Ursache dieses Effekts sollte in weiterfĂĽhrenden
Studien näher untersucht werden. Um belastbare Fütterungsempfehlungen zur
Prävention von Kalziumoxalatharnsteinen aussprechen zu können, sollten die
Ergebnisse dieser Arbeit in weiterführenden Untersuchungen an prädisponierten
oder erkrankten Katzen ĂĽberprĂĽft werden.This study aimed at investigating the effects of variations in sodium and
crude protein concentrations as well as protein quality in a diet on urine
composition of cats. In particular, risk factors for the formation of calcium
oxalate urine stones were evaluated. For this, seven experimental diets were
fed to 8 healthy adult cats. Diets varied in concentrations of sodium (0.38 %,
0.65 %, 1.14 % and 1.43 % in dry matter), crude protein (34.7 %, 43.8 % and
57.4 % in dry matter) and collagen-rich greaves meal (12 % and 35 % in the
diet). Each diet was fed for a three-week adaptation period and a subsequent
one-week collection period. For the collection periods, cats were housed
individually in metabolic cages to collect their urine and faeces. Feed and
water intake were recorded daily during the collection periods. Concentrations
of urinary anions and cations, relative supersaturation of the urine with
calcium oxalate and struvite as well as faecal dry matter, crude nutrient and
mineral concentrations were determined. The key findings of this study are
briefly listed below. Increasing levels of dietary sodium were associated with
an enhanced urine volume and renal sodium excretion. The concentration of
calcium in the urine of the cats was not affected, but the urinary excretion
of calcium increased from 0.62 to 1.05 mg/kg body weight/day with increasing
dietary sodium levels. Urinary oxalate, citrate, phosphorus and potassium
concentrations decreased at higher sodium intakes. The pH of the urine ranged
between 6.33 and 6.45 among the treatment groups (P > 0.05). The relative
supersaturation of the urine with calcium oxalate was not affected by varying
sodium levels in the experimental diets. Consequently, in the context of the
formation of calcium oxalate urine stones, this part of the study shows some
positive effects of a high sodium intake in cats over a short time. The
concentrations of calcium in the urine as well as the relative supersaturation
of the urine with calcium oxalate remained unaffected and the concentrations
of oxalate in the urine were reduced. This finding could especially contribute
to prevent the formation of calcium oxalate urine stones. With increasing
concentrations of crude protein in the diet, an enhanced urine volume could be
observed as well as an increase in urinary calcium concentrations, renal
calcium and oxalate excretion and relative supersaturation of the urine with
calcium oxalate. The pH of the urine ranged from 6.34 to 6.66 among all
groups, while no unidirectional influence of the dietary protein level could
be detected (P > 0.05). With the exception of the enhanced urine volume, these
effects of a high protein diet might be critical with regard to the prevention
of calcium oxalate urine stones in cats. When feeding the diet with a higher
percentage of collagen-rich greaves meal, less urinary excretion of calcium
could be detected.The reason for this effect remains unclear and should be
investigated in future studies. To be able to give reliable feeding
recommendations for the prevention of calcium oxalate urine stones, the
results of the present study should be verified through further investigations
in cats that are either predisposed or diseased