Main Research Findings

1) Administration with myo-inositol or microbial phytases has the potential to result in improved physical performance in broiler chickens.

2) Comparison of the effects of myo-inositol, phytases, and feeding monocalcium phosphate, there was an improvement in the nutritional quality of the resulting eggs laid by the hens fed the enhanced food.

 

Selected Data

1) The research team of Cowieson et al investigated the effects of myo-inositol and microbial phytase on physical performance and blood biochemistry parameters when fed diets that were either adequate or lacking levels of calcium. For the purpose of this study broiler chickens underwent two feeding trials that utilized a combined wheat/corn/soybean meal. 5% canola type full-fat rapeseed containing low glucosinolate and low erucic acid was added to the meal days 1-10, 10% was added to the meal days 11-20, and 12% was added to the meal days 21-42 of the experiment. In order to simulate the conditions of commercial production the pens the animals were kept in were surrounded by a commercial broiler flock containing birds of the same origin. Temperatures were maintained at 32 degrees Celsius and gradually lowered until reaching 21 degrees Celsius by day 21 of the experiment [2].

As it was previously mentioned there were two different feeding experiments conducted by the research team. The first experiment used 400 one day old male Ross 308 chicks. Each animal was randomly assigned to 1 of 4 different dietary treatments that included 10 pens per treatment and 10 birds to a pen. The 4 treatment groups were defined as follows: adequate calcium and dP with 0.15% myo-inositol; adequate calcium and dP without 0.15% myo-inositol; insufficient calcium and dP with 0.15% myo-inositol; and insufficient calcium and dP without 0.15% myo-inositol.

The second dietary experiment used 800 one day old male Ross 308 chicks that were randomly assigned to 1 of 8 different dietary treatments. The dietary treatments were defined as follows: adequate calcium and dP with 0.15% myo-inositol and with 500 phytase units; adequate calcium and dP with 0.15% myo-inositol and without 500 phytase units; adequate calcium and dP without 0.15% myo-inositol and with 500 phytase units; adequate calcium and dP without 0.15% myo-inositol and without 500 phytase units; insufficient calcium and dP with 0.15% myo-inositol and with 500 phytase units; insufficient calcium and dP with 0.15% myo-inositol and without 500 phytase units; insufficient calcium and dP without 0.15% myo-inositol and with 500 phytase units; insufficient calcium and dP without 0.15% myo-inositol and without 500 phytase units [2].

The birds were fed ad libitum with the wheat/corn/soybean meal containing 5% full-fat rapeseed from days 1-10, 10% from days 11-20, and 12% from days 21-42. Feed administered from day 1–10 was referred to as the starter diet, days 11-20 were referred to as the grower diet, and days 21 to 42 were referred to as the finisher diet. The rapeseed was prepared by grinding it with a roller mill to achieve an average mash particle size of less than 0.55 mm. Each dietary plan included varying levels of calcium and dP and were designed to be either isocaloric or isonitrogenous in order to meet or exceed breeder guidelines.

During the first dietary experiment the starter diet included pelleted and crumbled feed. That being said, during the secondary dietary experiment all feed was delivered to the birds in mash form that was prepared on a laboratory scale line equipped with horizontal double band mixers and roller mills. On the other hand, the pelleted food was prepared on a commercial line also equipped with a horizontal mixer and double conditioning pellets. The researchers noted that a laser thermometer was used to measure the temperature in the conditioner [2].

In order to calculate feed intake, body weight gain, and feed conversion ratio, the birds and their residual feed were weighed on days 11, 21, and 42. Any birds that had died were weighed and removed in order to calculate the percent mortality. During the second experimental trial blood biochemistry was investigated in addition to feed intake, body weight gain, and feed conversion ratio. At the end of the trial on day 42, blood samples were collected following a 1 hour fast via wing vein, from one randomly selected bird from each of the 10 replicate pens.

The serum was obtained by centrifuging the blood samples for 10 minutes and a radioimmunoassay commercial kit was used to determine levels of insulin and glucagon. Glycerol was measured using a method developed by Foster and Dunn while glucose was determined enzymatically utilizing glucose oxidase, o-dianisidine, and peroxidase. Commercial enzymatic assay kits were used to determine the concentration of high density lipoproteins and serum triglycerides. Spectrophotometry using a colorimetric method was used to analyze total P while total calcium was analyzed using a 4100 MP-AES plasma detector. Finally, phytase activity was determined using a method developed by Engelen et al that defined 1 FTU as the amount of enzyme needed to liberate 1 umol of inorganic P per minute derived from 5 mM sodium phytate [2].

2) The research team of Zyla et al assessed the effects of supplementation with myo-inositol and microbial phytases on the amount of yolk lipids and cholesterol as well as the fatty acid composition of the eggs laid. The experimental dietary protocol utilized 120 fifty week old Bovans Brown laying hens that were placed in individual cages on a wire-mesh floor under climate controlled conditions. Prior to the initiation of the dietary experiments the hens were fed a standard diet of corn and soybean meal that was compliant with nutritional recommendations set by the NRC. Once the animals reached 50 weeks of age they were assigned to 1 of 10 different dietary treatments that they were fed for 12 weeks. All food and water was provided to the animal ad libitum [3].

The 10 dietary treatments all including 3.65% calcium were defined as follows: 1) a negative control, corn and soybean meal diet with 0.08% NPP; 2) an internal control corn and soybean meal diet with 0.304 grams of monocalcium phosphate; 3) a negative control corn and soybean meal diet with 0.1% of myo-inositol; 4) a negative control corn and soybean meal diet with 1300 AcPU/kg of phytase B; 5) a negative control corn and soybean meal diet with 1300 AcPU/kg of phytase B and 300 FTU/kg of 6-phytase A; 6) a negative control, wheat and soybean meal diet with 0.08% NPP; 7) an internal control wheat and soybean meal diet with 0.304 grams of monocalcium phosphate; 8) a negative control wheat and soybean meal diet with 0.1% of myo-inositol; 9) a negative control wheat and soybean meal diet with 1300 AcPU/kg of phytase B; 10) a negative control wheat and soybean meal diet with 1300 AcPU/kg of phytase B and 300 FTU/kg of 6-phytase A [3].

In order to track changes elicited by the dietary treatments, the number and weight of eggs were registered daily in order to calculate egg production, while feed utilization was calculated at the end of the experiment. Feed utilization was expressed as grams of egg mass per gram of feed consumed. Additionally, egg mass was defined as the egg production x egg weight/100 while egg weight was defined as the mean weight of a single egg. Yolk lipid composition was analyzed in the eggs collected from the hens fed a corn and soybean meal diet by cooking the eggs for 15 minutes and separating the yolk for lyophilization. The shell breaking strength was assessed using an Instron Testing Machine on the eggs collected on day 84 of the experimental period. The eggs collected on day 87 of the experiment were used to assess total cholesterol levels by solubilizing yolk liophilizates in a 2% NaCl solution. Finally, the eggs collected on day 90 of the experiment underwent further analysis to determine shell density and thickness [3].

 

Discussion

1) The initial results of the experiment conducted by Cowieson et al revealed that total P and total calcium levels were as expected and near formulated values in both the first and second dietary experiments. When looking at phytase activity during experiment 2, the levels were calculated at 514 FTU/kg during the starter diet phase (days 1-10), 610 FTU/kg during the grower diet phase (days 11-20), and 580 FTU/kg during the finisher diet phase (days 21-42).

When assessing the effects of calcium and dP as well as myo-inositol on the physical performance of broiler chickens, mortality rates seemed to have decreased, however, there is not clear evidence suggesting the change is related to the diet. Overall, there were no significant changes in body weight gain, feed intake, or feed conversion ratio elicited by changes in calcium and dP concentrations. That being said, body weight gain was found to increase when 0.15% myo-inositol was added to a diet with insufficient calcium and dP. However, body weight gain was decreased with the addition of myo-inositol and insufficient amounts of calcium and dP [2].

These findings suggest a significant interaction between day 21 to 42 (the finisher diet), as well as a strong trend noted from day 1 to day 42. Additionally, the feed conversion ratio was shown to significantly decrease during the finisher diet phase from days 21 to 42 when myo-inositol was supplemented in the diet. The research team also noted that when adding 0.15% myo-inositol to the feed, feed conversion ratio was significantly higher during the starter diet phase from days 1 to 10.

In terms of the second dietary experiment, the effects of calcium, total P concentration and the addition of myo-inositol and microbial phytases, there was a notable decrease in mortality rates, however, it is unclear as to whether it is related to the dietary treatment. During the starter phase of the trial, days 1 to 10, insufficient levels of dP and Ca were found to impair feed conversion ratio and reduce body weight gain. When 0.15% myo-inositol was added during this phase without the addition of microbial phytases, there was a reduction in body weight gain and an increase in feed conversion ratio. However, when microbial phytases were present there was an increase in body weight gain and a reduction in the feed conversion ratio. These findings suggest a significant interaction between phytases and myo-inositol [2].

The results gathered during the grower phase, days 11 to 20, revealed that insufficient levels of calcium and dP led to lower body weight gain when compared to the animals with a diet containing adequate calcium and dP concentrations. There was a noticeable three-way interaction noted between the experimental factors that developed due to a decrease in feed intake resulting from the addition of myo-inositol that was restored by the addition of microbial phytase. Also in the presence of phytase, feed conversion ratio was found to decrease when myo-inositol was added to a diet of either adequate or insufficient levels of calcium and dP. These findings resulted in a strong interaction between phytase and myo-inositol for the feed conversion ratio.

Finally, during the finisher dietary phase, days 21 to 42, adding myo-inositol to both diets containing adequate and insufficient concentrations of calcium and dP resulted in an increase in body weight gain. However, body weight increase was greater in the group receiving adequate concentration of dP and calcium. In the presence of phytase, addition of myo-inositol did not result in an increase in body weight gain, feed conversion ratio, or feed intake. These findings suggested a significant interaction between phytase and myo-inositol for body weight gain with a potential interaction for feed conversion ratio and feed intake as well [2].

When looking at changes in the blood chemistry, addition of myo-inositol and phytase were shown to decrease blood glucagon concentration, however, the combined treatment had a synergistic effect on blood glucagon levels in the positive control diet. These findings suggest a strong three-way interaction between myo-inositol, phytase, and adequate levels of dietary calcium and dP. In terms of insulin concentrations, independent application of myo-inositol and phytase resulted in an increase in insulin concentration, however, this effect was muted with a combined treatment of myo-inositol and phytase. In terms of blood glucose concentration, levels were synergistically increased in the positive control diet and subadditivity increased in the negative control group when myo-inositol and phytase were added together. The increase in blood glucose was more notable in the negative control group with the addition of both myo-inositol and phytase.

Addition of phytase to the diet was found to reduce total cholesterol levels in the animals fed a positive control diet and increase total cholesterol levels in the animals fed a negative control diet. This indicated an interaction between phytase and concentrations of calcium and dP. When 0.15% myo-inositol was added to the diet there was a decrease in high-density lipoprotein cholesterol that occurred regardless of the presence of phytase of the concentrations of calcium and dP. When 500 FTU/kg of microbial phytase were added to the negative control diet there was an increase in blood triglyceride levels. The opposite effect was seen when phytase was added to the positive control diet. These findings suggest a significant interaction between phytase and the concentration of dP and calcium [2].

2) The results of the study conducted by the research team of Zyla et al reports that the Bovans Brown laying hens fed a diet of corn and soybean meal experienced significant changes in feed intake. In comparison, the laying hens fed a diet of wheat and soybean meal did not have a notable change in feed intake. When phytase B was added to the corn and soybean meal diet, there was an increase in feed intake that was similar to the increase noted with the internal control diet with 0.304 g/kg of MCP added. The addition of 6-phytase A with phytase B did not result in any further enhancements in feed intake in the laying hens. When myo-inositol was administered to the animals there was a decrease in the feed intake of the hens eating corn and soybean meal [3].

Next, changes in body weight were assessed at the end of the 12 week experimental period and reflected the amount of feed the birds ingested throughout the study. There was an average loss of 274 grams in the hens fed a corn and soybean meal diet, however, in the birds fed a wheat and soybean meal diet there were no significant changes in body weight. The most significant amount of weight lost was measured at 414 grams and noted in animals fed a corn and soybean meal diet with no supplementation of phytases and/or myo-inositol. On the other hand, the hens fed a diet of phytase B and 6-phytase A only lost an average of 138 grams. In comparison, when the animals were fed a diet of wheat and soybean meal by itself there was an average loss of 17 grams and when with phytase B and 6-phytase A supplemented there was an average gain of 64 grams.

As it was previously mentioned, feed utilization was calculated by the research team as the grams of egg per grams of feed; this parameter was not shown to significantly change with any of the experimental dietary treatments. Despite lack of significance, the research team noted that when 0.1% myo-inositol was added to the diet there was a slight decrease in feed utilization from 0.508 to 0.472. In the animals fed a diet of wheat and soybean meal there was an increase in the mass of eggs, mean weights, and hen-day egg production in comparison to the hens fed a corn and soybean meal diet. Overall, all dietary additions were found to elicit significant changes in egg mass and egg production [3].

In terms of yolk weight, yolk color, and eggshell quality parameters, there were significant changes noted in yolk weights, shell weights, shell thickness, shell density, and shell breaking strength in the eggs laid from hens fed a wheat and soybean meal diet. However, in the eggs laid from hens fed a corn and soybean meal diet, there were significant changes in yolk color determined by an increase in points on the Roche scale. Additionally, there was a positive trend in overall egg weight in the eggs collected from animals fed diets containing phytase B and/or 6-phytase A. The eggs collected from hens fed a diet containing myo-inositol also experienced an increase in egg mass that was greater than baseline levels. Similarly there was an increase in shell density and breaking strength seen in the groups fed phytase B and/or 6-phytase A and myo-inositol [3].

 

Disclaimer

**LAB USE ONLY**
*This information is for educational purposes only and does not constitute medical advice. THE PRODUCTS DESCRIBED HEREIN ARE FOR RESEARCH USE ONLY. All clinical research must be conducted with oversight from the appropriate Institutional Review Board (IRB). All preclinical research must be conducted with oversight from the appropriate Institutional Animal Care and Use Committee (IACUC) following the guidelines of the Animal Welfare Act (AWA).

 

Citations

[1] DiNicolantonio JJ, H O’Keefe J. Myo-inositol for insulin resistance, metabolic syndrome, polycystic ovary syndrome and gestational diabetes. Open Heart. 2022 Mar;9(1):e001989. doi: 10.1136/openhrt-2022-001989. PMID: 35236761; PMCID: PMC8896029.

[2] Cowieson AJ, Ptak A, Mackowiak P, Sassek M, Pruszynska-Oszmalek E, Zyla K, Swiatkiewicz S, Kaczmarek S, Józefiak D. The effect of microbial phytase and myo-inositol on performance and blood biochemistry of broiler chickens fed wheat/corn-based diets. Poult Sci. 2013 Aug;92(8):2124-34. doi: 10.3382/ps.2013-03140. PMID: 23873561.

[3] Zyla K, Mika M, Duliński R, Swiatkiewicz S, Koreleski J, Pustkowiak H, Piironen J. Effects of inositol, inositol-generating phytase B applied alone, and in combination with 6-phytase A to phosphorus-deficient diets on laying performance, eggshell quality, yolk cholesterol, and fatty acid deposition in laying hens. Poult Sci. 2012 Aug;91(8):1915-27. doi: 10.3382/ps.2012-02198. PMID: 22802186.

 

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