Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Aug;48(4):2761-2766.
doi: 10.1007/s11259-024-10399-9. Epub 2024 May 3.

Circadian rhythm of salivary and serum urea concentration in alpacas and sheep receiving diets with different levels of protein

Juan Olazabal-Loaiza  1   2 , Luis A Gomez-Puerta  3 , Felipe San Martín  3 , Carlos A Gómez-Bravo  4
Affiliations

Circadian rhythm of salivary and serum urea concentration in alpacas and sheep receiving diets with different levels of protein

Juan Olazabal-Loaiza et al. Vet Res Commun. 2024 Aug.

Abstract

All vertebrates possess a daily rhythm, encompassing a comprehensive set of physiological, cognitive, and behavioral patterns that manifest throughout a 24-hour period. The aim of this study was to compare the effect of crude protein (CP) levels in the diet on the daily rhythm of urea in serum (US) and saliva in alpacas and sheep. Ten alpacas and ten sheep, adult, clinically healthy males, were used; they were maintained in natural light conditions and fed ad libitum with two levels of CP (16 and 7%). Blood and saliva samples were taken every 4 h for 48 h. A two-way ANOVA was conducted to analyze the parameters, including adjusted mean rhythm (MESOR), amplitude, and acrophase. It was found that both US and saliva urea exhibited circadian rhythms with a peak during the midday (10:59 - 12:16 h). The MESOR with low CP diets was higher (P < 0.05) in alpacas. The MESOR of urea levels in saliva was greater (P < 0.05) at the highest level of CP in the diet, with no differences between alpacas and sheep (P > 0.05). The amplitude was greater (P < 0.05) in alpacas and at the high level of CP compared to the low level of CP in the diet. Our findings reveal that both serum and saliva urea levels in alpacas and sheep follow a daily rhythm and the MESOR of US was higher in alpacas when they consume food with low CP content, and this difference disappears when CP levels are increased in the diet.

Keywords: Alpacas; Circadian rhythm; Level crude protein; Nutrition; Sheep; Urea.

PubMed Disclaimer

Similar articles

See all similar articles

Cited by

References

    1. Assenza A, Fazio F, Marcenò G, Piccione G, Caola G (2009) Daily rhythms of serum and salivary parameters in goats. Aust Vet J 87(10):397–401. https://doi.org/10.1111/j.1751-0813.2009.00480.x - DOI - PubMed
    1. Cirio A, Méot F, Delignette-Muller ML, Boivin R (2000) Determination of parotid urea secretion in sheep by means of ultrasonic flow probes and a multifactorial regression analysis. J Anim Sci 78(2):471–476. https://doi.org/10.2527/2000.782471x - DOI - PubMed
    1. Cornelissen G (2014) Cosinor-based Rhythmometry. Theor Biol Med Model 11(1):1–24. https://doi.org/10.1186/1742-4682-11-16 - DOI
    1. Fawcett JK, Scott JE (1960) A rapid and precise method for the determination of urea. J Clin Pathol 13:156–159. https://doi.org/10.1136/jcp.13.2.156 - DOI - PubMed - PMC
    1. Folman Y, Neumark H, Kaim M, Kaufmann W (1981) Performance, rumen and blood metabolites in high-yielding cows fed varying protein percents and protected soybean. J Dairy Sci 64(5):759–768. https://doi.org/10.3168/jds.S0022-0302(81)82645-8 - DOI

LinkOut - more resources