The effect of sheep genetic merit and feed allowance on nitrogen partitioning and isotopic discrimination

Khanaki, H.; Dewhurst, Richard J.; Leury, Brian J; Cantalapiedra-Hijar, Gonzalo; Edwards, Grant; Logan, Chris M.; Cheng, Long

doi:10.1016/j.animal.2021.100400

Cited by 5 publications

(12 citation statements)

References 24 publications

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“…When diets were supplemented with urea to increase NI, which ranged from 22.1 and 23.5 to 27.6 g/day, the UN increased (C, C +0.5%, and C+1.2% excreted 6.7, 7.5, and 9.6 g/day, respectively; Figure 1). Moreover, when NI increased, manure N increased, which agrees with studies conducted in lactating dairy cows (Colmenero and Broderick, 2006;Kidane et al, 2018) and in mature rams Khanaki et al, 2021). The UN/NI ranged between 0.3 and 0.4 g/g, which was lower than reported by Brand et al (1992) and within the range observed in other studies (Bernard et al, 2020;Khanaki et al, 2021) increasing NI.…”

Section: Nitrogen Metabolism and Nitrogen Partitioningsupporting

confidence: 91%

“…Moreover, when NI increased, manure N increased, which agrees with studies conducted in lactating dairy cows (Colmenero and Broderick, 2006;Kidane et al, 2018) and in mature rams Khanaki et al, 2021). The UN/NI ranged between 0.3 and 0.4 g/g, which was lower than reported by Brand et al (1992) and within the range observed in other studies (Bernard et al, 2020;Khanaki et al, 2021) increasing NI. This result is consistent with the other reports (Niu et al, 2016;Kidane et al, 2018), which showed that as animals consume more N, there is less of an increase in FN than UN.…”

Section: Nitrogen Metabolism and Nitrogen Partitioningsupporting

confidence: 91%

“…In contrast, the main source of N in the urine is urea, which is reported to be depleted in 15 N (Steele and Daniel, 1978;Cheng et al, 2016). The range of plasma D 15 N values in this study is higher than the range stated in previous studies (Cheng et al, 2013a;Cheng et al, 2016;Bernard et al, 2020;Khanaki et al, 2021). We have no explanation for the differences between these previous studies and our current study, as all sheep were healthy and unstressed throughout the experiment.…”

Section: Nitrogen Metabolism and Nitrogen Partitioningcontrasting

confidence: 86%

“…The less efficiently the animals use dietary N, the higher the plasma D 15 N (Sick et al, 1997;Cheng et al, 2013a andCheng et al, 2013b;Cantalapiedra-Hijar et al, 2018). Some other studies (Cheng et al, 2011;Bernard et al, 2020;Khanaki et al, 2021) showed that the NUE decreased when NI increased. However, in the present study, NUE did not change when NI increased from treatment C to treatment C+1.2%.…”

Section: Nitrogen Utilization In Relation To Nitrogen Isotopic Discri...mentioning

confidence: 95%

“…Previous studies showed that digestion, rumen function, and metabolism may differ between large and small ruminants (Lapierre and Lobley, 2001;Doreau et al, 2003;Kawashima et al, 2007). Since most cited studies are with large ruminants, more research is still required (Lavery and Ferris, 2021;Khanaki et al, 2021) to explore this relationship, particularly as only three studies can be found (Cheng et al, 2013a;Bernard et al, 2020;Khanaki et al, 2021). The NI measurement is hard to measure in grazing systems, though it is needed to quantify N use efficiency (NUE) and UN/NI.…”

Section: Introductionmentioning

confidence: 99%

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Relationship Between Nitrogen Isotopic Discrimination and the Proportion of Dietary Nitrogen Excreted in Urine by Sheep Offered Different Levels of Dietary Non-Protein Nitrogen

Khanaki

Dewhurst²,

Leury³

et al. 2022

Front. Anim. Sci.

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Urinary nitrogen (N) excretion (UN) as a proportion of N intake (NI; UN/NI) is a major determinant of N excretion from ruminants and could be predicted from the N isotopic discrimination occurring between dietary and animal proteins (Δ15N). This study investigated the usefulness of Δ15N and other plasma biomarkers to reflect changes in UN/NI from sheep offered different levels of dietary urea. Eighteen Merino rams (age, 1–2 years; live weight, 41 ± 3 kg) were allocated to three dietary N treatments for a N balance study. Treatments were control (C), control + 0.5% urea (C+0.5%), and control + 1.2% urea (C+1.2%) and designed to provide maintenance, maintenance plus an additional 15%, and maintenance plus an additional 33% NI, respectively. The urea effect term was used for one-way ANOVA and regression analysis. As NI increased, the UN and retained N (RN) increased linearly (p < 0.001), but UN/NI only increased in treatment C+1.2% compared with C (p < 0.05). Plasma Δ15N was positively and significantly correlated with UN and UN/NI (r = 0.52, p = 0.028; and r = 0.68, p = 0.002, respectively) and increased linearly (p < 0.001) with the highest values observed in C+1.2%. Urine δ15N changed linearly between C and C+1.2%, but plasma δ15N increased quadratically (p < 0.05). Plasma urea N increased in a linear way across dietary urea levels (p < 0.001). The N isotopic difference between plasma and urine (plasma δ15N–urine δ15N) of C did not vary from either of the other treatments; however, it differed between C+0.5% and C+1.2% (p < 0.05). The study confirmed the potential usefulness of plasma Δ15N to estimate UN/NI from sheep. Moreover, plasma δ15N–urine δ15N can be proposed as a new biomarker of N excretion from small ruminants. These approaches, however, need to be tested in various study conditions.

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Section: Nitrogen Metabolism and Nitrogen Partitioningsupporting

confidence: 91%

Section: Nitrogen Metabolism and Nitrogen Partitioningsupporting

confidence: 91%

Section: Nitrogen Metabolism and Nitrogen Partitioningcontrasting

confidence: 86%

Section: Nitrogen Utilization In Relation To Nitrogen Isotopic Discri...mentioning

confidence: 95%

Section: Introductionmentioning

confidence: 99%

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Relationship Between Nitrogen Isotopic Discrimination and the Proportion of Dietary Nitrogen Excreted in Urine by Sheep Offered Different Levels of Dietary Non-Protein Nitrogen

Khanaki

Dewhurst²,

Leury³

et al. 2022

Front. Anim. Sci.

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Alterations in nutrient digestion and utilization associated with different residual feed intake in Hu sheep

Zeng¹,

Yin²,

Chen³

et al. 2023

Animal Nutrition

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Effects of rumen-bypass protein supplement on growth performance, hepatic mitochondrial protein complexes, and hepatic immune gene expression of beef steers with divergent residual feed intake

Idowu,

Taiwo,

Sidney

et al. 2023

Preprint

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We investigated the impact of a rumen-bypass protein supplement on growth performance, plasma and urinary N concentration, hepatic mitochondrial protein complexes, and hepatic mRNA expression of immune genes of beef steers with negative or positive residual feed intake (RFI) phenotype. Forty crossbred beef steers with an average body weight (BW) of 492 ± 36 kg were subjected to a generalized randomized block design over a 42-day experimental period. This study followed a 2 × 2 factorial arrangement of treatments. The factors evaluated were: 1) RFI classification (low-RFI (-2.12 kg/d) vs. high-RFI (2.02 kg/d), and 2) rumen-bypass protein supplement: rumen-bypass protein supplement (RCP; 227 g/steer/d) vs. control diet (CON; 0 g/d), resulting in four distinct treatments: Low-RFI-CON (n = 10), low-RFI-RCP (n = 10), high-RFI-CON (n = 10), and high-RFI-RCP (n = 10). The rumen-bypass protein supplement (84% CP) is a mixture of hydrolyzed feather meal, porcine blood meal, and DL-methionine hydroxy analogue. The beef steers were stratified by BW and randomly assigned to treatments and housed in four pens (1 treatment/pen) equipped with two GrowSafe feed bunks each to measure individual DMI. Body weight was measured every 7 d. Liver tissue samples were collected on d 42 from all the beef steers. These samples were used for mRNA expression analysis of 16 immune-related genes and for evaluating the mitochondrial protein complexes I - V. No significant effects due to RCP supplementation or RFI × RCP interactions (P > 0.05) were observed for ADG and DMI. However, compared to high-RFI steers, low-RFI steers showed a trend towards reduced DMI (12.9 vs. 13.6 kg/d; P = 0.07) but ADG was similar for the two RFI groups. Regardless of RFI status, supplemental RCP increased blood urea nitrogen (BUN) (P = 0.01), with a lower BUN concentration in low-RFI steers compared to high-RFI ones. A tendency for interaction (P = 0.07) between RFI and RCP was detected for urinary N concentrations; feeding RCP diet increased the urinary concentration of urea-N in high-RFI beef steers (209 vs. 124 mM), whereas the concentration was lower than that of the CON group for low-RFI beef steers (86 vs. 131 mM). Interactions of RCP and RFI were observed (P ≤ 0.05) for mitochondrial activities of complexes IV, V, and mRNA expressions of some immune genes such as TLR2, TLR3, and IL23A. In conclusion, while RCP supplementation didn't alter growth performance, its observed effects on hepatic immune gene expression, mitochondrial protein complexes, BUN, and urinary urea nitrogen depended on the beef steers' RFI phenotype. Further studies are warranted to understand the mechanisms underpinning the interactions between RCP supplementation and RFI status.

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The effect of sheep genetic merit and feed allowance on nitrogen partitioning and isotopic discrimination

Cited by 5 publications

References 24 publications

Relationship Between Nitrogen Isotopic Discrimination and the Proportion of Dietary Nitrogen Excreted in Urine by Sheep Offered Different Levels of Dietary Non-Protein Nitrogen

Relationship Between Nitrogen Isotopic Discrimination and the Proportion of Dietary Nitrogen Excreted in Urine by Sheep Offered Different Levels of Dietary Non-Protein Nitrogen

Alterations in nutrient digestion and utilization associated with different residual feed intake in Hu sheep

Effects of rumen-bypass protein supplement on growth performance, hepatic mitochondrial protein complexes, and hepatic immune gene expression of beef steers with divergent residual feed intake

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