Effects of lauric acid on ruminal protozoal numbers and fermentation pattern and milk production in lactating dairy cows1

Abstract

The objectives of this study were to evaluate lauric acid (LA) as a practical ruminal protozoa-suppressing agent and assess effects of protozoal suppression on fermentation patterns and milk production in dairy cows. In a pilot study, 6 lactating Holstein cows fitted with ruminal cannulae were used in a randomized complete-block design trial. Cows were fed a basal total mixed ration (TMR) containing (DM basis) 15% alfalfa silage, 40% corn silage, 30% rolled high moisture shelled corn, and 14% solvent soybean meal, and assigned to 1 of 3 treatments: 1) control, 2) 160 g/d of LA, or 3) 222 g/d of sodium laurate, which is equimolar to 160 g/d of LA, all given as a single dose into the rumen via cannulae before feeding. Both agents showed high antiprotozoal activity when pulse dosed at these amounts via ruminal cannulae, reducing protozoa by 90% (P<0.01) within 2 d of treatment. Lauric acid reduced ruminal ammonia concentration by 60% (P<0.01) without altering DMI. Both agents reduced ruminal total free AA concentration (P<0.01) and LA did not affect ruminal pH or total VFA concentration. In a large follow-up feeding trial, 52 Holstein cows (8 with ruminal cannulae) were used in a randomized complete-block design trial. Cows were assigned to 1 of 4 diets and fed only that diet throughout the study. The TMR contained (DM basis) 29% alfalfa silage, 36% corn silage, 14% rolled high moisture shelled corn, and 8% solvent soybean meal. The 4 experimental diets were similar, except part of the finely ground dry corn was replaced with LA in stepwise increments from 0 to 0.97% of dietary DM, which provided (as consumed) 0, 83, 164, and 243 g/d of LA. Adding these amounts of LA to the TMR did not affect DMI, ruminal pH, or other ruminal traits, and milk production. However, LA consumed at 164 and 243 g/d in the TMR reduced the protozoal population by only 25% and 30% (P=0.05), respectively, showing that these levels, when added to the TMR, were not sufficient to achieve a concentration within the rumen that promoted the antiprotozoal effect of LA.

Effects of macauba cake on profile of rumen protozoa of lambs

“…The latter could have caused toxic effect on ciliate protozoa due to its high levels of unsaturated fatty acids, considerable levels of lauric (C 12:0 ) and myristic (C 14:0 ) acids (Table 1). Both in vitro and in vivo studies have demonstrated protozoa sensitive to linolenic (C 18:3 ), linoleic (C 18:2 ), and oleic (C 18:1 ) unsaturated fatty acids, in this order (Machmüller et al, 1998;Hristov et al, 2004), and to lauric and myristic saturated fatty acids (Dohme et al, 1999;Faciola et al, 2013), with greater antiprotozoal effects observed with medium chain saturated lipids (Machmüller et al, 1998).…”

“…Other mechanisms for lipid toxicity that have been proposed were: perturbation of ether-lipid metabolism; inhibition of a specific-acyl-CoAacyltransferase, an enzyme involved in lipid-remodelling (Lux et al, 2000); and inhibition of methylation of phosphatidylcholine, which would block neo synthesis (Lira et al, 2001). Even though these studies were in flagellated protozoa, which have different membrane structure than rumen ciliates, these mechanisms may shed light into possible lipid toxicity mechanisms in rumen ciliates (Faciola et al, 2013).…”

Efeito da inclusão da torta de macaúba na população de protozoários do rúmen de vacas leiteiras

“…1). Nesse sentido, pesquisas realizadas in vitro e in vivo demonstraram que os protozoários são sensíveis aos ácidos graxos insaturados oleico (C18:1 cis-9), linoleico (C18:2 cis-9 cis-12) e α-linolênico (C18:3 n-3) (Machmüller et al, 1998;Hristov et al, 2004) e aos ácidos graxos saturados láurico e mirístico (Dohme et al, 1999;Faciola et al, 2013), sendo os dois últimos os que apresentam maior efeito tóxico sobre os protozoários ciliados do rúmen (Machmüller et al, 1998 A predominância do gênero Entodinium está de acordo com as observações dos autores que investigaram as populações de protozoários no rúmen de bovinos alimentados com dietas contendo óleo de soja, associado ou não à monensina (Martinele et al, 2008), de ovinos criados na caatinga (Matos et al, 2008), de bovinos e bubalinos alimentados com dietas suplementadas com monensina ou própolis (Risponli et al, 2009) e em caprinos submetidos à dieta com casca de soja, em substituição ao milho (Carvalho et al, 2011). Essa predominância pode ser justificada por esse gênero apresentar várias espécies de ampla distribuição e ocorrência entre vários ruminantes domésticos e selvagens (Ogimoto e Imai, 1981 A atividade antiprotozoária da TM na dieta poderia ter efeito positivo na eficiência de utilização da energia da dieta, uma vez que os protozoários podem ser responsáveis por até 37% de metanogênese (Finlay et al, 1994), e, portanto, uma redução dos ciliados pode resultar em menor perda de energia a partir do rúmen.…”

“…Essa predominância pode ser justificada por esse gênero apresentar várias espécies de ampla distribuição e ocorrência entre vários ruminantes domésticos e selvagens (Ogimoto e Imai, 1981 A atividade antiprotozoária da TM na dieta poderia ter efeito positivo na eficiência de utilização da energia da dieta, uma vez que os protozoários podem ser responsáveis por até 37% de metanogênese (Finlay et al, 1994), e, portanto, uma redução dos ciliados pode resultar em menor perda de energia a partir do rúmen. Além disso, pesquisadores têm relatado que a supressão de protozoários está intimamente relacionada com a redução da concentração de amônia no rúmen e o aumento da eficácia da síntese de proteína microbiana (Faciola et al, 2013;Fiorentini et al, 2013).…”

Topical and Vapor Toxicity of Saturated Fatty Acids to the German Cockroach (Dictyoptera: Blattellidae)

“…For example, there is evidence that antimicrobial synergy occurs in combinations of short-and long-chain fatty acids (Wang 1983). Fatty acids are toxic to both blood-borne (Doering et al 1994) and intestinal protozoa (Faciola et al 2012). Therefore, it is possible that fatty acids could be used to target cellulose-digesting protozoa in the guts of termites, resulting in individual and colony starvation.…”