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Nitrogen partitioning and isotopic discrimination are affected by age and dietary protein content in growing lambs

  • M. Bernard (a1), L. Cheng (a2), C. Chantelauze (a3), Y. Song (a2), A. Jeanleboeuf (a4), L. Sagot (a5) and G. Cantalapiedra-Hijar (a3)...


It is difficult to separate an age-dependent fall in nitrogen use efficiency (NUE; N balance/N intake) in growing ruminants from a progressively decrease in animal protein requirements over time. This study examined the effect of dietary protein content on N partitioning, digestibility and N isotopic discrimination between the animal and its diet (Δ15Nanimal-diet) evaluated at two different fattening periods (early v. late). Twenty-four male Romane lambs (age: 19 ± 4.0 days; BW: 8.3 ± 1.39 kg) were equally allocated to three dietary CP treatments (15%, 17% and 20% CP on a DM basis). Lambs were reared with their mothers until weaning, thereafter housed in individual pens until slaughter (45 kg BW). During the post-weaning period, lambs were allocated twice (early fattening (30 days post-weaning) and late fattening (60 days post-weaning)) to metabolic cages for digestibility and N balance study. When diet CP content increased, the average daily gain of lambs increased (P < 0.05) while the age at slaughter decreased (P = 0.01), but no effect was observed on feed efficiency (P > 0.10). Diet CP content had limited effect on lamb carcass traits. Higher fibre digestibility was observed at the early v. late fattening period (P < 0.001). The N intake and the urinary N excretion increased when diet CP content increased (P < 0.001) and when shifting from early to late fattening period (P < 0.001). Faecal N excretion (P = 0.14) and N balance (P > 0.10) were not affected by diet CP content. Nitrogen digestibility increased (P < 0.001) as the diet CP content increased and on average it was greater at late v. early fattening period (P = 0.02). The NUE decreased (P = 0.001) as the diet CP content increased and as the lamb became older (P < 0.001). However, the age-dependent fall in NUE observed was lower at high v. low dietary CP content (CP × age interaction; P = 0.04). The Δ15Nanimal-diet was positively correlated (P < 0.05) with N intake (r = 0.59), excretion of faecal N (r = 0.41), urinary N (r = 0.69) and total manure N (r = 0.64), while negatively correlated with NUE (r = −0.57). Overall, the experiment showed NUE was lower in older lambs and when lambs were fed high diet CP content, and that Δ15Nanimal-diet was a useful indicator not only for NUE but also for urinary N excretion, which is a major environmental pollution factor on farm.


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Atti, N, Rouissi, H and Mahouachi, M 2004. The effect of dietary crude protein level on growth, carcass and meat composition of male goat kids in Tunisia. Small Ruminant Research 54, 8997.
Association of Official Analytical Chemists (AOAC) 2005. Official methods of analysis, volume 2, 18th edition. AOAC, Washington, DC, USA.
Aufrère, J 1982. Etude de la prévision de la digestibilité des fourrages par une méthode enzymatique. Annales de Zootechnie 31, 111130.
Aufrère, J and Cartailler, D 1988. Mise au point d’une méthode de laboratoire de prévision de la dégradabilité des protéines alimentaires des aliments concentrés dans le rumen. Annales de Zootechnie 37, 255270.
Bernard, M, Jeanleboeuf, A, Sagot, L, Cheng, P, Quereuil, A and Cantalapiedra Hijar, G 2018. The nitrogen use efficiency in growing lambs is negatively impacted by both the dietary protein content and the age of animals: towards a phase-feeding approach. In Proceedings of the 10th International Symposium on the Nutrition of Herbivores, 6–9 September 2018, Clermont-Ferrand, France, pp. 158–159.
Black, JL and Griffiths, DA 1975. Effects of live weight and energy intake on nitrogen balance and total N requirements of lambs. British Journal of Nutrition 33, 399413.
Bruckmaier, RM, Gregoretti, L, Jans, F, Faissler, D and Blum, JW 1998. Longissimus dorsi muscle diameter, backfat thickness, body condition scores and skinfold values related to metabolic and endocrine traits in lactating dairy cows fed crystalline fat or free fatty acids. Journal of Veterinary Medicine Series A 45, 397410.
Cantalapiedra-Hijar, G, Dewhurst, R, Cheng, L, Cabrita, ARJ, Fonseca, A, Nozière, P, Makowsky, D, Fouillet, H and Ortigues-Marty, I 2018. Nitrogen isotopic fractionation as a biomarker for nitrogen use efficiency in ruminants: a meta-analysis. Animal 12, 18271837.
Cantalapiedra-Hijar, G, Ortigues-Marty, I, Schiphorst, AM, Robins, RJ, Tea, I and Prache, S 2016. Natural 15N abundance in key amino acids from lamb muscle: exploring a new horizon in diet authentication and assessment of feed efficiency in ruminants. Journal of Agricultural and Food Chemistry 64, 40584067.
Cantalapiedra-Hijar, G, Ortigues-Marty, I, Sepchat, B, Agabriel, J, Huneau, JF and Fouillet, H 2015. Diet–animal fractionation of nitrogen stable isotopes reflects the efficiency of nitrogen assimilation in ruminants. British Journal of Nutrition 113, 11581169.
Castillo, AR, Kebreab, E, Beever, DE and France, J 2000. A review of efficiency of nitrogen utilization in lactating dairy cows and its relationship with environmental pollution. Journal of Animal and Feed Sciences 9, 132.
Chen, D, Sun, J, Bai, M, Dassanayake, KB, Denmead, OT and Hill, J 2015. A new cost-effective method to mitigate ammonia loss from intensive cattle feedlots: application of lignite. Scientific Reports 5, 16689.
Cheng, L, Al-Marashdeh, O, McCormick, J, Guo, X, Chen, A, Logan, C, Tao, JZ, Carr, H and Edwards, G 2017. Live weight gain, animal behaviour and urinary nitrogen excretion of dairy heifers grazing ryegrass–white clover pasture, chicory or plantain. New Zealand Journal of Agricultural Research 61, 454467.
Cheng, L, Edwards, GR, Dewhurst, RJ, Nicol, AM and Pacheco, D 2015. The effect of dietary water soluble carbohydrate to nitrogen ratio on nitrogen partitioning and isotopic fractionation of lactating goats offered a high-nitrogen diet. Animal 10, 779785.
Cheng, L, Kim, EJ, Merry, RJ and Dewhurst, RJ 2011. Nitrogen partitioning and isotopic fractionation in dairy cows consuming diets based on a range of contrasting forages. Journal of Dairy Science 94, 20312041.
Cheng, L, Nicol, AM, Dewhurst, RJ and Edwards, GR 2013. The effects of dietary nitrogen to water-soluble carbohydrate ratio on isotopic fractionation and partitioning of nitrogen in non-lactating sheep. Animal 7, 12741279.
Deniro, MJ and Epstein, S 1981. Influence of diet on the distribution of nitrogen isotopes in animals. Geochimica et Cosmochimica Acta 45, 341351.
Di, HJ and Cameron, KC 2002. Nitrate leaching in temperate agroecosystems: sources, Factors and mitigating strategies. Nutrient Cycling in Agroecosystems 64, 237256.
Dijkstra, J, Oenema, O, van Groenigen, JW, Spek, JW, van Vuuren, AM and Bannink, A 2013. Diet effects on urine composition of cattle and N2O emissions. Animal 7, 292302.
Faisant, N, Planchot, V, Kozlowski, F, Pacouret, MP, Colonna, P and Champ, M 1995. Resistant starch determination adapted to product containing high level of resistant starch. Sciences des Aliments 15, 8389.
Haddad, SG, Nasr, RE and Muwalla, MM 2001. Optimum dietary crude protein level for finishing Awassi lambs. Small Ruminant Research 39, 4146.
Hajji, H, Smeti, S, Hamouda, MB and Atti, N 2016. Effect of protein level on growth performance, non-carcass components and carcass characteristics of young sheep from three breeds. Animal Production Science 5, 21152121.
Institut national de la recherche agronomique (INRA) 2007. Nutrition of cattle, sheep and goats: animal needs–values of feeds. Éditions Quae, Paris, France.
Institut national de la recherche agronomique (INRA) 2018. Feeding system for ruminants. Wageningen Academic Publishers, Wageningen, the Netherlands.
Lobley, GE 1993. Species comparisons of tissue protein metabolism: effects of age and hormonal action. Journal of Nutrition 123, 337343.
MacRae, JC, Walker, A, Brown, D and Lobley, GE 1993. Accretion of total protein and individual amino acids by organs and tissues of growing lambs and the ability of nitrogen balance techniques to quantitate protein retention. Animal Science 57, 237245.
Meale, SJ, Auffret, MD, Watson, M, Morgavi, DP, Cantalapiedra-Hijar, G, Duthie, CA and Dewhurst, RJ 2018. Fat accretion measurements strengthen the relationship between feed conversion efficiency and nitrogen isotopic discrimination while rumen microbial genes contribute little. Scientific Reports 8, 3854. doi: 10.1038/s41598-018-22103-4.
National Research Council 1994. Nutrient requirements of poultry. National Academy Press, Washington, DC, USA.
National Research Council 1998. Nutrient requirements of swine. National Research Council Press, Washington, DC, USA.
National Research Council 2012. Nutrient requirements of swine: Eleventh Revised Edition. National Academies Press, Washington, DC, USA.
National Research Council 2016. Nutrient requirements of beef cattle. National Academies of Sciences, Engineering, and Medicine (NASEM), 8th revised edition. National Academy Press, Washington, DC, USA.
Ørskov, ER, McDonald, I, Grubb, DA and Pennie, K 1976. The nutrition of the early weaned lamb. IV. Effects on growth rate, food utilization and body composition of changing from a low to a high protein diet. The Journal of Agricultural Science 86, 411423.
Sick, H, Roos, N, Saggau, E, Haas, K, Meyn, V, Walch, B and Trugo, N 1997. Amino acid utilization and isotope discrimination of amino nitrogen in nitrogen metabolism of rat liver in vivo. Zeitschrift für Ernährungswissenschaft 36, 340346.
Spanghero, M and Kowalski, ZM 1997. Critical analysis of N balance experiments with lactating cows. Livestock Production Science 52, 113122.
Sponheimer, M, Robinson, T, Ayliffe, L, Roeder, B, Hammer, J, Passey, B, West, A, Cerling, T, Dearing, D and Ehleringer, J 2003. Nitrogen isotopes in mammalian herbivores: hair δ15N values from a controlled feeding study. International Journal of Osteoarchaeology 13, 8087.
Van Soest, PV, Robertson, JB and Lewis, BA 1991. Methods for dietary fiber, neutral detergent fiber, and nonstarch polysaccharides in relation to animal nutrition. Journal of Dairy Science 74, 35833597.
Varel, VH, Nienaber, JA and Freetly, HC 1999. Conservation of nitrogen in cattle feedlot waste with urease inhibitors. Journal of Animal Science 77, 11621168.
Veira, DM, Macleod, GK, Burton, JH and Stone, JB 1980. Nutrition of the weaned Holstein calf. II. Effect of dietary protein level on nitrogen balance, digestibility and feed intake. Journal of Animal Science 50, 945951.
Vérité, R and Delaby, L 2000. Relation between nutrition, performances and nitrogen excretion in dairy cows. Annales de Zootechnie 49, 217230.
Wattiaux, MA and Reed, JD 1995. Fractionation of nitrogen isotopes by mixed ruminal bacteria. Journal of Animal Science 73, 257266.
Wheadon, NM, McGee, M, Edwards, GR and Dewhurst, RJ 2014. Plasma nitrogen isotopic fractionation and feed efficiency in growing beef heifers. British Journal of Nutrition 111, 17051711.
Willms, CL, Berger, LL, Merchen, NR, Fahey, GC and Fernando, RL 1991. Effects of increasing crude protein level on nitrogen retention and intestinal supply of amino acids in lambs fed diets based on alkaline hydrogen peroxide-treated wheat straw. Journal of Animal Science 69, 49394950.


Nitrogen partitioning and isotopic discrimination are affected by age and dietary protein content in growing lambs

  • M. Bernard (a1), L. Cheng (a2), C. Chantelauze (a3), Y. Song (a2), A. Jeanleboeuf (a4), L. Sagot (a5) and G. Cantalapiedra-Hijar (a3)...


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