Natural alternative growth promoters, a new frontier

With the ban of antibiotics used as growth promoters (AGP) in several regions worldwide, nutritionists have tried to use additives based on plant extracts to improve performance of broilers to the same level as AGP. If the initial intention was to use plants extracts for their antimicrobial activity, research has shown their broader range of effects on gut functions, such as 1. the modulation of microbiota composition and activity: Certain plant extracts can limit the growth or virulence of certain pathogens while have limited effect on 'good' bacteria. Or 2. the stimulation of digestive functions: Several plant extracts increase the activity of endogenous digestive enzymes and influence uptake and transepithelial transport and improve nutrients digestion and absorption. Or 3. the modulation of immune response: Specific molecules contribute to lower gut inflammation while other molecules modulate cytokines production from macrophages or down/up regulate the expression genes coding for cytokine production to keep inflammation under control, or support development of acquired immunity. Or finally 4. the improvement of gut integrity: Some molecules or natural ingredients stimulate mucous production and epithelial cell proliferation and therefore contribute to the maturation and integrity of the gut structure. Besides, during the last decade, research has highlighted the importance of micro- encapsulation technology to guarantee the protection and the release of phytogenic compounds in the digestive tract, to avoid the waste or degradation of active ingredients and ensure consistent efficacy.

Phycogenics: New molecules from marine algae

Phytogenics are of great importance in animal nutrition, and marine macroalgae can be considered as supplements to positively influence animal performance and health parameters. Seaweeds represent a large and heterogeneous group, including brown algae (Phaeophyceae), red algae (Rhodophyceae) and green algae (Chlorophyceae). While algae are frequently studied as a source of nutrients, seaweeds possess several bioactive molecules, so called 'phycogenics' (from Greek Phycos = Algae), that are studied for their prebiotic, anti-microbial, antioxidant, anti-inflammatory and immune-modulatory effects. Few examples of molecules exclusively found in marine algae are sulfated polysaccharides, phlorotannins and laminarins.

Research has shown the effects of several compounds and metabolites, and their specific impact of physiology. Here is a short list of molecules or groups of molecules from seaweeds, that have been specifically studied: natural polyphenols such as phlorotannin, tocopherol, bromophenol (antioxidant activity); sulfated polysaccharides or fucoidans (Immune enhancer); natural pigment (to improve egg/meat color) or also specific complex polysaccharides (Prebiotic affect). Phycogenics are not meant to replace phytogenics, but they represent a fantastic portunity to new metabolites with potential benefits on health of humans and animals.

Comparing 'standard' phytogenics with 'advanced' phytogenics

A recent trial was performed at the Faculty of Veterinary Medicine, Mahanakorn University of Technology (Thailand), to compare the effects of 4 treatments. The first treatment consisted in a basal diet with classic corn/soybean formulation (Negative Treatment, NC). The second treatment consisted in the same basal diet with the supplementation of one commercial solution based on phytogenics (Positive Control, PC) at 100g/ton of feed. The 3^rd and 4^th treatment consisted in the same basal diet, with the addition of one new feed additives technology, based on the micro-encapsulation of phytogenics & phycogenics, with 2 different doses, either 75g/ton of feed for 35 days or with 100g/ton of feed till 21 days and then 75g/ton till the end (NUQO^© technology, NQ1 & NQ2). The dietary periods were divided in two phases: starter diet (1-21 days) and grower diet (22-35 days) which are 22% CP; 3,100 Kcal ME/kg and 20% CP; 3,150 Kcal ME/kg, respectively. All diets were mash feed. All birds were given ad libitum access to feed and drinking water. Routine medication, vaccination, and husbandry practices were administered.

During this trial, researchers measured various parameters: Growth performance data were collected and analyzed for accumulated periods of 1 to 21, 22 to 35, and 1 to 35 days of age. The body weight, body weight gain, feed intake, and feed conversion ratio of all treatments were analyzed. Gut microbial concentrations were assessed at 35 days of age. Caecum contents were used to determine the amount of lactic acid bacteria and Clostridium perfringens. Cloacal swab samples were used to determine the Salmonella spp. Gut morphology was assessed on jejunum samples collected at day 14 and 35 of age. The villus height and crypt depth were determined in cross section using inverted microscope. The villus height-to-crypt depth ratios were calculated. Oxidative enzyme concentrations were assessed in blood samples collected at day 21 and 35 of age.

Concerning performance, during the overall period (d1-35), birds fed with PC treatment showed little difference with the control group NC. Birds fed NQ2 or NQ1 showed better erformance than birds in the control group: +3,6% and +2,6% feed intake and +2,3% and +1,9% body weight gain, respectively. NQ1 & NQ2 treatments showed as well a significant improvement of FCR compared with PC treatment. To conclude both dosages of NUQO^© NEX improved performance of broiler chickens, but birds fed NQ2 had an overall better performance than birds fed NQ1.

In parallel, NQ treatment reduced the level of C. perfringens in broiler chickens without affecting beneficial bacteria, which reflects a positive effect on gut microbial population. Besides, when analysing the villi height in jejunum, one can see that both NQ1 and NQ2 treatments improve the total absorptive area of the small intestine in a dose-dependent manner. The villi height to crypt depth ratio was similar to that of the NC, indicating that the cell renewal for longer villus height did not come at the costs of energy for growth.

Micro-encapsulated phytogenics and phycogenics as a new standard

The market of phytogenics has increased substantially during the last decade. Of course, not all solutions are the same, with different formulation, different technology and of course some discrepancies in terms of 'transparency' and scientific backup. There is now common acceptance around the effects of phytogenics but also higher standards and expectations. Nutritionists needs clear information about the mode of action of metabolites from plants (phytogenics) or marine algae (phycogenics). It is also important to work with advanced manufacturing technologies, that guarantee the stability, the release and consistent efficacy of these solutions. A new generation of products, with clear formula and technology, can be used as alternative or sustainable growth promoter. Recent research has shown a higher but also more consistent effect to support performance of animals. Such technology can be used to increase performance or to optimize formulation and reduce feed costs to cope with market conditions.

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Article made possible through the contribution of NUQO

Optimizing performance with a new generation of growth promoters