Effect of reduced dietary non-phytate phosphorus concentration, with or without calcium reduction, in diets supplemented with phytase for weaned piglets from 28 to 63 days of age
Published:January 7, 2020
By:A. N. Sélos 1, J. L. Donzele 2, R. F. M. O. Donzele 2, T. R. Castro 1 , E. F. Cardoso 3, L. N. Rennó 2 and D. A. M. Braga 2. / 1 School of Veterinary Medicine and Animal Science, Universidade Federal do Tocantins, Araguaína, Tocantins, Brazil; 2 Department of Animal Science, Universidade Federal de Viçosa, Peter Henry Rolfs Avenue, s/n, Campus Universitário, Viçosa, Minas Gerais, Brazil; 3 Instituto Federal de Educação, Ciência e Tecnologia Baiano (Campus Itaberaba), Bahia, Brazil.
Summary
The aim of this study was to investigate the impact of reduced dietary non-phytate phosphorus (nPP) or nPP and calcium (Ca) concentrations in diets supplemented with phytase on performance, bone mineralisation and serum parameters of weaned piglets from 28 to 63 days of age. A total of 168 barrows and gilts, weaned at 28 days of age, with an average initial bodyweight of 8.11 ± 0.61 kg were randomly allocated in a completely randomised block design. Treatments consisted of a positive control and an additional six treatments, in a 3 × 2 factorial arrangement, totaling seven treatments (Trt). The positive control (PC) diet was formulated to meet or exceed the nutrient requirements of pigs weighing 8–30 kg bodyweight, without phytase supplementation, and the six other diets were formulated similar to the PC, except with a reduction in the nPP concentration of 0.065, 0.130 or 0.195% (Phase Feeding 1 (PF1), PF2 or PF3 respectively) or similar to PF1, PF2 and PF3 minus 0.16% Ca, supplemented with 2000 FTU/kg of phytase, with eight replicate pens/Trt of three piglets each, in a three-phase feeding program. From Day 28 to Day 35, the average daily gain was higher (P < 0.05) and the feed conversion rate was lower (P < 0.05) respectively for piglets fed the PC when compared with those fed PF3 and PC treatment minus 0.160% calcium and minus 0.195% nPP (PF6). In contrast, when evaluating the period from Day 28 to 49, piglets fed PC presented the highest average daily gain, but only differed (P < 0.05) to those fed PF3 and PF6. When considering the overall period, at 63 days of age, no significant difference was detected (P > 0.05) between the PF Trts tested and the PC regarding performance. As for bone mineralisation at 63 days, bone P (BP) decreased as nPP in the diet decreased, regardless of the Ca level. However, except for PF3 and PF6, BP and third metacarpal bone ash concentration were respectively higher for pigs fed the PF Trts, when compared with PC. All treatments containing phytase resulted in a lower bone Ca : BP ratio when compared with PC. Serum P concentrations decreased as nPP in the diet decreased, regardless of the level of dietary Ca. However, with the exception of PF3 and PF6, serum P was not significantly different than pigs fed the PC. In conclusion, reducing nPP or nPP and Ca in diets containing 2000 FTU Ronozyme® HiPhos/kg phytase had no adverse effects on growth performance and increased BP and third metacarpal bone ash concentration compared with pigs fed a nutritionally adequate control diet.
Dear Prof. Donzele.
Since Hiphos concentration is expressed in FYT, I believe that when you write FTU you mean FYT, right? Considering it has an equivalence around a 2:1 ratio to FTU, your level was really 1000 FTU/kg. Thank you.
How 2000 FTU vs 1000 depend upon 2 things: Total P of diet or level of PP. when limited, high dose phytase not to perform; The Phytase, not all one same, specially for pig. wide pH profile win longer time to digest PP.
Dr Kryukov, I do not intend to dispute the issue, but in my understanding we have two main focuses in research, namely, basic and applied. I realize, from your considerations, that your vision is the advancement of science by science, generating basic information, without concern for the applied character of the research. . I respect your opinions, but I do not agree with all of them because I understand that conducting practical research is also doing science. I even think that applied research is the way we have to validate information obtained in the basics. As for your questioning that you always want something new that drives science, it confirms what I think about your research vision, and therefore, I think that you are not included in the target audience of this study. Finally, I say that I have no reason to be offended, quite the contrary, because I understand that in biology there is no owner of the truth. And that in science the contradiction is what makes it the development
Valerij Kryukov, I understand that with your proposed evaluations, the objective to be achieved would be to prove the effective action of phytases in the hydrolysis of phytate, which was not the intention of this study. As for the dosage question, we used 2000 FTU / Kg based on a study available in the literature, where the authors found a linear effect of phytase concentration up to 2000 FTU / Kg in the feed on the performance of the piglets. Now the fact that the phytase concentrations of 800 - 1000 FTU / Kg would result in the same efficiency as the concentration of 2000 FTU / Kg was not proven in that work. I understand that this study would be restricted if the phytase concentration below was used of the 800 FTU / Kg, I believe that with the evaluations that were carried out, the objectives of the study were fully achieved. Thus, it can be deduced that the evaluated parameters were sufficient to validate the conclusions of this study. As for the questioning that the study explains nothing, it gives the understanding that a study in which it is proposed to evaluate levels of calcium and phosphorus in the diet with phytase supplementation, would only be valid if it used phytase in the concentration between 800 to 1000 FTU / Kg and that the evaluations were made in the intestinal digestion and in the feces. I reaffirm that these assessments would be essential if we were specifically evaluating the efficiency of action of phytase, which was not the case. .. I also understand that if you go into this detail, the phytase action of the intestinal mucosa of piglets should be evaluated. I also understand that the evaluations of blood and bone parameters performed reflect in some way the effectiveness of the action of phytase. I make these considerations in the sense that I am aware of my limitations and that I did not intend with this work to put an end to the researched subject.
I assume that the dose of 2000 FTU/kg is too high. Similar results could be obtained by including 800-1000 FTU/kg in the feed. The study reflects only the facts of experience and the authors do not explain anything. Perhaps the explanation is in the full article. Reducing the calcium content in the diet, even without adding phytase, increases the absorption and use of phosphorus. For the development of research, it is interesting to determine the content of total and phytate phosphorus in feces. I suggest the formation of secondary phytates in the small intestine, which may reduce the availability of phosphorus. It is interesting to collect the contents of the jejunum (between jejunum and Ileum) and incubate in vitro with phytase Ronozyme ® HiPhos and Qwantum Blue. This will allow you to find out the effectiveness of phytase (preserving its activity) in the lower intestine. It is also interesting to incubate feces, which will help you find out whether the phytases completely break down the feed's phytates/
I wish you success!
Prof. Valerij Kryukov
