Effects of supplying leucine and methionine to early-lactating cows fed silage-concentrate based diets with a calculated deficiency in leucine and methionine Thomas Kröber, Franz Sutter, Markus Senn, Wolfgang Langhans, Michael Kreuzer To cite this version: Thomas Kröber, Franz Sutter, Markus Senn, Wolfgang Langhans, Michael Kreuzer. Effects of sup- plying leucine and methionine to early-lactating cows fed silage-concentrate based diets with a calcu- lated deficiency in leucine and methionine. Animal Research, EDP Sciences, 2001, 50 (1), pp.5-20. 10.1051/animres:2001102. hal-00889920 HAL Id: hal-00889920 https://hal.archives-ouvertes.fr/hal-00889920 Submitted on 1 Jan 2001 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Anim. Res. 50 (2001) 5–20 5 © INRA, EDP Sciences, 2001 Original article Effects of supplying leucine and methionine to early-lactating cows fed silage-concentrate based diets with a calculated deficiency in leucine and methionine Thomas F. KRÖBERa, Franz SUTTERa, Markus SENNb, Wolfgang LANGHANSb, Michael KREUZERa* a Group of Animal Nutrition, Institute of Animal Sciences, Swiss Federal Institute of Technology (ETH), ETH centre/LFW, 8092 Zurich, Switzerland b Group of Physiology and Animal Husbandry, Institute of Animal Sciences, Swiss Federal Institute of Technology (ETH), ETH centre/LFW, 8092 Zurich, Switzerland (Received 30 August 1999; accepted 7 September 2000) Abstract — In a 2 × 2 factorial approach the productive and metabolic response of 24 multiparous Brown Swiss cows fed rations calculated to be deficient in leucine (0.9-fold of requirements) and methionine (0.8-fold) to supplementation either of one or both of these amino acids were investigated. On a dry matter basis the rations consisted of 29% grass silage, 20% maize silage, 6% hay, and 45% concentrate. Blood plasma amino acid data confirmed the intended difference in metabolic supply of leucine and methionine keeping a low variation in the plasma levels of the other essential amino acids, particularly lysine. Live weight, milk yield as well as content and amount of milk fat were not affected by the treatments. Content and amount of milk protein were significantly reduced relative to initial level without additional methionine. Nutrient digestibility and nitrogen balance remained widely unchanged by the supplementations. Except of plasma aspartate amino transferase, cholesterol, creatinine and ornithine, which responded to methionine, hormones, enzyme activities as well as plasma, urine and milk metabolites were not systematically influenced by leucine and methionine sup- ply. The present results gave clearer indications for a deficiency in methionine than in leucine. amino acids / dairy cow / requirements / leucine / methionine Résumé — Effets de l’apport de leucine et méthionine chez des vaches en début de lactation rece- vant des rations ensilage-concentré à déficit calculé en leucine et méthionine. Vingt-quatre vaches laitières multipares Brown Swiss ont été affouragées avec des rations calculées pour être déficientes en leucine (0,9 fois du besoin) et méthionine (0,8 fois). Les effets d’une supplémentation de l’un ou des deux acides aminés sur la production et le métabolisme de ces vaches ont été exami- nés à l’aide d’une approche factorielle 2 × 2. En matière sèche, les rations étaient composées de 29 % d’ensilage d’herbe, 20 % d’ensilage de maïs, 6 % de foin et 45 % de concentrés. Comme * Correspondence and reprints Tel.: 41 1 632 5972; fax: 41 1 632 1128; e-mail: [email protected] 6 T.F. Kröber et al. prévu, les analyses des acides aminés dans le plasma sanguin ont confirmé une disponibilité méta- bolique différente de la leucine et de la méthionine, alors que les autres acides aminés essentiels n’ont montré que peu de variation, en particulier la lysine. Le poids vif, la production et la compo- sition du lait, ainsi que la quantité de ses matières grasses n’ont pas été affectés par les traitements. Sans méthionine supplémentaire la teneur et la quantité de protéines dans le lait ont diminué signi- ficativement par rapport au niveau initial. La digestibilité des nutriments et le bilan azoté sont restés inchangés malgré les supplémentations. Les taux hormonaux et les activités enzymatiques sanguins, ainsi que les métabolites du sang, de l’urine et du lait le plus souvent n’ont pas répondu clairement à l’adjonction de leucine et méthionine. Les résultats suggèrent l’existence d’une déficience en methionine plutôt qu’en leucine. acides aminés / vache laitière / besoins / leucine / méthionine 1. INTRODUCTION limiting amino acid in dairy cows [4]. Even mixed forage rations containing maize silage fed together with concentrate might be defi- Most of the commonly applied systems cient in leucine depending on the propor- of recommendations for protein supply of tion of concentrate and the type of concen- dairy cows are based on the protein available trate ingredients used. It is not yet completely in metabolism after small intestinal diges- clear in which order methionine and leucine tion. Although ruminants, like monogastric are required for maximum metabolic pro- animals, have distinct requirements for sin- tein utilisation, and more reliable informa- gle amino acids rather than for protein, only tion is still needed on the cow’s require- very few systems of recommendations, such ments for leucine particularly in relation to as the modified French PDI [34] and the methionine and the types of rations in which Dutch DVE system [8], give the option to these amino acids are actually limiting. consider also the dietary supply of limiting amino acids. Fickler and Heimbeck [11] The objective of the present study was suggested a factorial approach to estimate to determine the degree of limitation by the supply of ‘metabolisable’ amino acids leucine independent from methionine using in order to be able to identify limiting amino a mixed basal ration with a calculated defi- acids. Knowledge on limitations in individ- ciency of leucine and methionine but not of ual amino acids allows to supplement these lysine. Performance, N balance and various amino acids at minimum additional nitro- metabolic indicators in blood, urine and gen intake thus also avoiding unnecessary milk, including the blood amino acid pro- environmental pollution by excretion of file, were determined in order to identify an excessive nitrogen. Methionine and lysine actual deficiency of leucine and of methio- are often regarded as limiting amino acids in nine. dairy cows, particularly with high dietary proportions of maize products rich in leucine [32]. This was recently confirmed by adding 2. MATERIALS AND METHODS lysine and methionine to a forage-based diet calculated to be deficient in these amino 2.1. Feed and treatments acids according to the modified French sys- tem [21]. However, under different feeding A balance experiment based on a 2 × 2 conditions such as forage-based grass/grass factorial design (deficient/sufficient supply silage rations instead of concentrate-based of leucine and methionine, respectively) was rations leucine might be the first or second performed with 24 early-lactating cows, Leucine and methionine requirements of dairy cows 7 with a total of six replicates per treatment (PDI), digestible lysine and methionine to group. In detail, the experiment was carried ensure compatibility of requirement and out in three subsequent experimental periods supply calculations. Accordingly, adequate with three groups of eight cows each (two supply of net energy and PDI was given in cows per treatment in each period). On a all groups. When net energy and absorbable dry matter basis, the rations were composed protein contents were calculated from prox- of forage (consisting of 53% early growth- imate analyses (Tab. I) by the Swiss system stage, rye grass dominated grass silage, 37% [12], in all groups a slight lack of net energy maize silage and 10% late growth-stage was calculated (not given in the tables) as it meadow hay) and concentrate in a ratio of is common for early lactating cows. Nitro- 1.2:1. Feed amount was individually allo- gen (crude protein) intake was sufficient to cated for each cow according to actual milk ensure maximum rumen fermentation activ- yield and live weight. The analysed nutri- ity [12] although some of the concentrate ent and amino acid composition of the feed ingredients contained protein of a relatively ingredients is given in Table I. low rumen degradability. Leucine supply was increased from low Table II also gives the results of two dif- supply (Leu-) to higher supply (Leu+) only ferent calculations of metabolic supply of by changing the ingredient composition of amino acids. One is based on the French the concentrate. The Leu- concentrate con- concept of digestible amino acids [33, 36] sisted on a dry matter basis of dried sugar which considers lysine (LysDI) and methio- beet pulp 20.0%, soy hulls 18.0%, barley nine (MetDI). For calculation of supply by 15.0%, citrus pulp 12.0%, wheat bran this approach INRA [35] feed tables on the 10.0%, maize germ 7.0%, soybean meal contents of LysDI and MetDI in feedstuffs 6.5%, wheat gluten meal 4.5%, sugar beet were used and requirement data of Rulquin molasses 4.0% and mineral premix 3.0%. et al. [33, 36] were applied. Accordingly, The Leu+ concentrate was similarly com- methionine was clearly deficient without posed except that the 4.5% wheat gluten supplementation and calculated require- meal (poor in leucine) were replaced by ments were fully covered with addition of 6.0% maize gluten meal, which should guar- methionine which increased supply by 23% antee a high leucine flow to the small intes- on average (p < 0.001).