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Plant alkaloids improve gut health and feed conversion in pigs

Plant alkaloids prove to be perfect alternatives for antimicrobial growth enhancers. Field trials conducted all over the world show that their antiinflammatory property supports gut health and the efficient use of feed.

Modern pig farmers looking to finisher feed strategies include the Guangzhou Fine Breed swine farms, Guangzhou, Guangdong, PR China

By Dr Steven McOrist, Asian Agribusiness Consulting, Beijing, China and Julia Schmitt, Product Management, Phytobiotics Futterzusatzstoffe, Eltville, Germany

Feed costs are widely recognised as the major factor in the cost of production of market pigs globally, with rapidly rising costs and diminishing availability of many animal feed components, such as corn, wheat and soybeans. This has led to strategies to identify feed additives that may improve the digestibility and resulting feed conversion from available feeds. For over 50 years, in-feed antibiotics have been highly successful for this role, but in the past ten years, the major reduction in registrations of new antibiotics, with a global increase in regulatory restrictions in their use, has led to a strong search for alternatives.

Anti-inflammatory properties
Certain plant alkaloids, such as Quaternary Benzophenanthridine and Protopine Alkaloids (QBA+PA) were identified as possible contenders for use as an alternative, due to their botanical activity as a secondary plant metabolite often a part of the plant response to injury. Their active role became more public some years ago, when QBA+PA were produced out from plants of the Papaveracaea family for specific use in oral anti-inflammatory products for humans. The anti-inflammatory effect of QBA+PA in this term is well documented in cell culture and physiological tests up to present.

QBA+PA is also evaluated in animal production trials as a useful additive to benefit animals performance in this matter.

Inflammatory processes have an impact on animal production as they require considerable amounts of energy and nutrients. Some interesting thesis in this matter is the observation that many antibiotics, formerly or still used in some countries as an AGP, show anti-inflammatory effects. Taking also the relatively low dosages of those in-feed antibiotics in account it can be assumed that the performance enhancing effect of AGPs is more a result of lowering inflammation than of acting as an antimicrobial. Thus active substances showing antiinflammatory properties are from a high point of interest for animal production.

Benefits of QBA+PA
The use of QBA+PA in animal production is now being taken up widely in form of a value added feed additive marketed as Sangrovit (Phytobiotics Feed Additives, Germany), in many countries and situations, as part of an antibiotic reduction strategy, particularly in terms of the role of feed additives needed for improved feed intake, digestibility and feed conversion.

Some of those data are sifted in a large number of controlled farm studies into an overview analysis. Further a meta-analysis on institute trials with piglets was done for the production phase of nursery pigs. Both overview data show the clear benefit of QBA+PA on feed conversion ratio, which is an important factor in regards to profitability and also can be an indirect indicator for animals’ health.

Meta-analysis on nursery pigs
This meta-analysis conducted at Hogeschool Gent (Belgium) included five different institute trials in Spain, Netherlands, Poland and Hungary. Pigs in the nursery phase on each site were assigned randomly to groups and fed test or matched control diets both based on a routine starter phase diet for five or six weeks, from the age of weeks 4 to 9 or 10.

Three different levels of QBA+PA were tested (15, 30 and 60 mg/kg feed). The feed intake and weight gain of all pigs were measured in the same manner at the start and finish of each institute trial.

The results of this meta-analysis on feed conversion ratio (FCR) for the five European pig trials are shown in Figure 1. A total of 1,742 pigs were present in these studies. There was a overall significant reduction of the feed conversion ratio of 3.1, 3.7 and 4.9% in the 15, 30 and 60 ppm QBA+PA groups respectively.

Field trial analysis
Pigs in the grower-finisher phase on each site were assigned randomly to groups and fed, test or matched control diets (supplemented and non-supplemented diets as representative in the tested regions) both based on a routine grower phase diet for 14 weeks, from the age of weeks 10 to 24. The feed intake and weight gain of all pigs were measured for each farm study.

The numbers of trials used in this analysis were conducted with a dosage range of QBA+PA as recommended by the manufacturer (15-50 mg/kg feed). The individual farm results of this analysis for feed conversion ratio (FCR) for 36 pig farms, located in across Europe and in Thailand, Mexico, Chile and Brazil are shown in Figure 2. There as an average reduction of the feed conversion ratio of 3.4% in the pigs in the tested QBA+PA groups.

Besides other projects, the feed additives company is currently incorporating a further farm study in China. The current breeding figures with sows imported in 2011 from the United Kingdom are return-to-service rate of 15%, farrowing rate of 80%, average number of piglets born of 11.8, average number of piglets born alive of 10.5 to 10.8, with an average weight at weaning (24 days old) of 5.8 kg.

The wide variety of farms and situations indicates that these quaternary benzophenanthridine and protopine alkaloids form a reliable active ingredient for reduction of gut integrity and feed conversion benefits hen used orally in pigs at appropriate doses. The commercial QBA+PA product has been licensed for several years with assays for the active ingredient and a traceable chain of production and formulation. This feed additive does not have a direct anti-microbial effect in the dosages as recommended by the manufacturer it is assumed that the mode of action of these plant alkaloids appears to be via anti-inflammatory activity within a focus on the gut mucosa.