High calcium intake in chickens.

Abstract

HIGH CALCIUM INTAKE IN CHICKENS M.W. MC DONALD* and T. SHAFEY** SUMMARY The effect of supplying the young chicken with calcium in excess of its requirements has been examined in some detai 1 Excess calcium has been shown to reduce growth rate and increase feed conversion ratio, but the effect is inconsistent. Genetic effects on the response have been identified. The reduction in growth is considered to result from altered calciumnot phssphorus ratios as both calcium carbonates and phosphates and depress growth, Increasing the electrolytes, sod i urn potassium, does not effect the response to excess' calcium. Biotin addition reduces the effect on feed conversion ratio., l Hi g,h cdl ci urn intake has been shown not t o influence nitrogen metabolisable energy or nitrogen retention but reduces utilization and increases the faecal excretion of fatty acids as soaps. Chickens fed high calcium diets deposit fats with a lower palmitic and stearic acid and higher linoleic acid content' INTRODUCTION of Recommended minimum calcium intake of chickens is 0.9 to i.C)% the diet (ARC and NRC). O'Del1 (196c,), McDonald and Sol vyns (1963) (I and McCl Vmont Sathe and McClymont (1965 a,b) q `Kondos (1967) : Karunajeewa Bryden and Ealnave (1983) ' anh Johnson and the (1984)' a l l found that calcium intake in excess of 1.2% of diet depressed growth, Connor and Neil 1 (1971), Rogler and Parker U972) and Karuna jeewa ( 1977) observed no depressi on w i t h L6, 1~57 and 1,45% calcium respectively. Commercial practice in some parts of Austral i a and New Zealand is to allow t h e mas imum calcium level of broiler diets to rise to as high as 1.6 to L8Xr indicating that any reduction in performance that might occur i; this range is of little economic significance. High calcium intake has been associated with excessive deami nati on af amino acids (Kondos and McClymont,. 1967) (I kidney . damage ( Corti na and San Gabriel. 1972). increased i nci dence of abnormal i ties (Ogura, 198i 1 and keduced availability o f leg b i o t i n (bryden a n d Balnave; 198Z% . This investigation aimed at identifying rea5ons the for differences in results obtained by different investigations and to develop methods for overcoming problems any physiological resulting from feeding high calcium dietr;, ---IIIL----------------------rr----------------------------------- X Dept. of Animal Husbandry, Q. A. Cm q Lanes, Q. 4343 ** Dept. of Animal Husbandry, Facul tb of Agriculture, . University of Queens1 and z St. Lucia 4067' 195 EXPERIMENTS The experiments described in this report were carried uut cm meat-type chickens, housed in single chick cages in a controlled environment. Chickens were usual 1 y fed a commerci;al broiler Gtarter from hatching to about b days, then fed the experimental diets for Pl-12days. Only a brief dekription of each es er i men t is supplied. 1 0 BMW--B--- in w-- w--w -a Variation -a response is clear from repeated experiments that excess calcium in depressi on, ThiiE; diet does not produce a consistant growth be seen by the comparison of growth depressions observed by can and more recently by F'laisted (1983L In McDonald and Solvyns, dietary calcium ranging from 0.9 to 23% was the first report, Pl ai sted fed and weight gains declined significantly above 1.3Xr a n g i n g f r o m 0.8 to 2.21;5 t o broiler levels of calcium fed gain She observed no consistant trend al though weight chickens. 1.8%. at 1 .2% calcium was significantly ip0L05) higher than at and Pl ai sted Results reported by McDonald, and Solvyns (1963 (1983) are contrasted in table 1. the It difference have been examined to esplain this that Factors intestinal flora and 1 imestone, particle size of added and electrolyte bakce i n the diet different antibiotics, The genotype of the chicken has been calcium phosphorus balance(I between identified as possibly contributing t.o the differences experiment resultsare experiments Compar i son of results of two TABLE 1 examining the effect of added calcium.on growth rate of chickens. 196 We have repeated this experiment, as a source of phosphate (Table 3). using di cal ci urn phosphate In the earlier experiment, both calcium carbonate and calcium phosphate depressed growth anb increased F.C.R. so it is unlikely that the growth depression produced by the carbonate was due to upsetting the calcium phosphorus balance. In the second series of experiments, changing the calcium phosphorus ratio b y adding calcium carbonate failed to produce a signif icant depression of growth or to increase F.C.R. in one experiment, but did so in the second In the experiment in which calcium depkessed performance, dicalcium phosphate produced a significantly greater depressi on than the carbonate. In the experiment in which calcium carbonate failed to depress growth rate, dicalcium phosphate also failed to . do so. l TABLE 3 Compar i son of the effect o f es cess calcium, supplied as calcium carbonate or dicalcium phosphate, on chick: growth and F.C.R. The original observations on high calcium intake were made in experiments in which different meatmeal s were compared. Diets 197 containing high levels of meatmeal also tend to contain high sodi urn 1 eve1 s. McDonal d and Sol vynti (1.964) found no cJif ference in the effect of high calcium, either as carbonate or- pho&phatx, in diets with or without 0.4%`added sodium (Table 4). (Table 5). This experiment has been repeated in the present ser i es The rsubstitution o f vegetable protein concentrates for meatmeal has raised the potassium content of chicken diets. This suggested that the lack of depression in some commercial diets might be related to the higher potassium intake. This3 was not supported by experimental results (Table 6). Increased calcium intake was found to significantly (pW.05) reduce weight gain a n d both i n the presence or increase F.C.R.. absence of added potassium carbonate (0.56% E). These results have been examined after the technique o f Monjin (1980) but analysis of electrolyte balance does not help in understanding the absence of an effect of sodium or potassium on the depressi o n , o r t h e variation in response from one TABLE 6 E f f e c t of experiment to another. calcium, potassium on the period 12 days. response t o esces5 198 Bryden and Ealnave (19831 found that high calcium intake in broilers reduced the level of plasma biotin, as well as reducing growth rate. Possible effect of biotin subplementation o n the growth depression due to high calcium intake, has been examined . in two experiments. because the first experiment, wheat and sorghum were compared of the lower availability of biotin in wheat (Whitehead, et al I) 1982) High calcium intake increased F.C.R. but did n o t affect weight gain. Biotin supplementation imcreased weight gain and reduced F.C.R. in the wheat based diets, but not i n the sorghum based diet. High calcium intake increased F.C.R. in the absence of biotin supplementation, but not in its presence. Grain calcium supplementation interactions were not type bY In l significant. TABLE 7 Effect of biotin on growth depression due to high calcium intake. In the second experiment, biotin was added to diets to which calcium was added as carbonate or phosphate (Table 8). Added calcium carbonate in produced a non-significant depressi on growth. Di-calcium addi ti on produced a sii gni f i cant phosphate reduction in growth and increase in F.C.R.. Addition of biatin did not effect weight gain but did prevent the increase in F.C.R. _ when dicalcium phosphate was added. 199 5. - - - - - I - - - - m - - - - Genetic effects- nutrition possibility that genotype a5ses5 the responses, four inconsistant interactions may account for the depasi t i on strain5 of chickens selected for growth rate and fat by F'ym (1980) g were compared. The strains were: To C W L F Each control selected for high 8 week weight. selected for low abdominal fat. selected for high abdominal fat. strain was fed diets containing 1.0% or 2.0% calcium. weight gain and reduced intake significantly High calcium increased F.C.R.. When strains were examined individually, strain . strains W and C showed non-significant L demonstrated no ef feet, while strain F depression of growth rat& and increase in\ F.C.Rrq increase in growth reduction ' signif icant and demonstrated a F.C.R. (Table 9) a TABLE 9 >Cornparison of growth and feed conversion responses of four strains of chicken to increased calcium intake. ,Plasma electrolytes were analysed. Strain F differed from the other three strains in demonstrating a lower rise in plasma total but a ,higher rise in ionised calcium than the calcium other strains5 when the high calcium diet was fed. All strains showed a in plasma phosphate, when the high calcium redtiction diet was fed, but in strain F this reduction was not significant (pX~35). .. . i n t a C:: e high calcium reduces In rats7 _ nitrogen and increases the excretion of fatty i975). Part of the effect of calcium an Sugai 1 possibly due to the formation of relatively soaps from dietary fatty acids. The the retention of acids (Goto and fat absorption is insoluble calczium metabolizable ral ci urn 5oap and ni tr-sgen utilization U4.M.E.) `1 faecal were measured utilization was cakulated as the percentage of . absorbed frnm the alimentary canal. N. retention was i nqestxd N* cai~d ated as the percentage of ingested N. retained in new energy l N: effect of calxium intake on appar- ent ti ssuh Results are summarised in table 10. Increasing intake, either by adding calcium carbonate or monahydrogen phosphate, did not inf hence the A.M.E. of the basal calkium intake significantly diet. The high the depressed nitrogen utilization but not the nitrogen retention. Connor and Neil1 also found that increased calcium intake did not (1971) effect observed M. E. values of the diet or nitrogen retention. Overal 1 digestability o f fatty acids was not significantly reduced there was a significant increase in t h e but amount of fatty acids escreted as soaps. TABLE 10. Effect of excess calcium'intake on A.M.E.,-. utilization and faecal soaps. nitrogen was Analysis of the composition of carcass fat showed that there a reduction in the amount of palmitic (16:C)) and stearic (18:C)) acids in t h e tissue lipids. This was off set by an increase in linoleic acid (18:2). This suggests that the increase in f decal soaps was 1 argel y d u e tb the formation o f calcium palmi tate and stearate. If fats are lost in this way, when high cdl c i urn diets are fed, it is surprising that an effkt on M.E. was not observed. 201 . The reduction in nitrogen utilization may have resulted from change in the intestinal pH,. a from 3.91 to 6.18 in a si mi 1 ar experiment. However nitrogen retention did not ref 1 ect the decrease in utilization when excess calcium was fed. A possible explanation might follow from the observation that the duodenum was 26% thinner when excess calcium was fed,. wall than when a normal diet was ingested. CQNCLUSIONS The results presented suggest that it is not clear h o w high calcium intake depresses chicken growth rate or increases feed conversion ratio. There are some indications that the ultimate effect is to depress feed intake (e.g. Saville, 1968). This might serve to esplain genetic effects as strains of birds d i f f e r i n the strength of the processes control 1 i ng feed intake and se1 ection for growth rate may result in increasing appetite o f the birds (tin,. 1981). escess calcium affects nitrogen metabolism was reported That We are now by Kondos and McClymont and confirmed in this study. acids. looking at effects on the availability of specific amino The interaction with biotin may idicate a specific effect, but i s more l i k e l y a general effect on availability o f a range of vi tamins again as suggested by some of Sathe and McClymont's and The significance of the effect on Kondos and McClymont's data. fat utilization needs further study. ACKNOWLEDGEMENTS A.C. Kondos is thanked for for analytical advice. Dr. A. Dr Cl ague: Fathol ogy Department, Royal Brisbane Hospital provided facilities a n d assisted with p&ma electrolyte analyses. Mr. F. Gorbacz assisted with the management of the chicks. Inghams and White Wi ngsb have been generous with chickens; Dr. R . Fym, the speci al 1 y University of Queens1 and supp 1 i ed selecteb chickens. The research was partially funded by the Chicken Meat Research Fund. REFERENCES ERYDEN, W.L. and BALNAVE, D. (1983) P- r o c .- - - - - - - w - Far East and Sth.- B e W.F.S.A. M-w M-L- - - - - - Facifik Fed., - - - e - - - - p. 104 Adelaide - - - - - - - we-CONNOR, J.K. and NEILL, fi.R. (1971) Aust. J. - Exe. - - - - - A n i m . Agric. - MY--. -m-w- -Husb., 11:383 --w-CORTINA, . GOTO,. M.M. and SAN GABRIEL A. (1972) CA.& abstr. 405939 S. a n d SUGAI, T . Cl973 NM--m- Reports - I --vn: 11.1:49 utr. - - - - nt Proc -w-el JOHNSON, R. 3. and KARUNAJEEWA H . (1984) Research em----m-m- - - -m--- a-wFoundat i on Symeosi urn 1984, Sydney -w--e----- Poultry ------ Hush .---- KARUNAJEEWA, H. (1977) Aust.-w -3. Exe. Agric. Anim - - - - - 17: 944 -m--m - - --WOW8 mm----: Husb l 202 KONDOS. AX. and McCLYMONT G.L. (1967) Proc. 1967 Poultry -w-w- a--- -m---Conv.,' Surfers Paradise p.95 --s-- ----w-w ----w--B LIN, C.Y. (1981) W . P . S . A . - J. 37:106 ---w-m-w - Science ---w-e- MCDONALD, M. W. and SOLVYNS A. (1964) Froc. B-w-Skfers Paradise CQn_Y:, -----w- e-w----- p-112 1964 Poultry Science ---- w----- ------- MONGIN, . F. (1980) Proc. e---- 1980 -em-: w-e---- -B-e- ---- --w-w-w- Sth Pacific Pod. Sci. Conv. p-364 O'DELL,. E.L. (1960) F --e- . ----a 19x548 ed Froc. OGURA, Y. . (1981) Nat. Inst. ---em -c---M --m---a- 21 (3): 141 -e-e --q-m Anim. Health Quarterly ROSEMARY J. (1983) Thesis for 8. App. PLAISTED, Q.A.C. 3 iawes,. Q Sci. (Rural Tech. 1, . ROGLER, J.C. and PARKER, H.E. (1972) . . SATHE, E. S . -J. ---LB 1021699 - Nutr. 16:24k - and McCLYMONT (1965 a) A u s t . J -. ----- Aqric. ---- Res. ---- and - - - (1965 b) Aust. -m-M- J.- figric. --- Res. -m-B 16: 491 SAVILLE,. D.G. (1968) Proc. Aust. Soc. Anim. Prod. 6:418 --s-m e--e- e--- ----- ----ARMSTRONG J.A. and WHITEHEAD, C.C., J. N u t r . h&81 m- a-m-- WADDINGTON D. (1982) Brit. --e-w 203