Research in Veterinary Science 1999, 66, 179–184
`Article No. rvsc.1998.0223, available online at http://idealibrary.com on
`
`An evaluation of iron-dextran supplementation in piglets
`administered by injection on the first, third or fourth
`day after birth
`
`A. K. EGELI, T. FRAMSTAD, Norwegian College of Veterinary Medicine, Department of Reproduction
`and Forensic Medicine, POB. 8146 Dep. 0033 Oslo, Norway
`
`SUMMARY
`
`The aims of the study were to evaluate the effect of iron-dextran injection given on the first, third or fourth day after birth on haema-
`tology in piglets. An advanced automated blood analyser; Technicon H*1®, which performs a complete blood cell count and leuko-
`cyte differential counts was used to analyse the blood. Six litters of Norwegian Landrace x Yorkshire piglets were included in the
`study. The day after birth (day 1), half of the piglets in each litter (split litters) were injected subcutaneously with 180 mg iron as
`iron-dextran (1·5 ml Idofer®). The untreated piglets from two of the litters were injected with the same amount of iron-dextran on
`day 3, and those from the remaining four litters on day 4. The piglets were weighed and blood samples collected on days 1, 3 or 4,
`7, 14 and 21. Erythropoiesis, but not leukocyte count, responded to injection on day 1 compared with injection on the third or fourth
`day. The difference between groups in haematological parameters was greatest on day 7. The two groups of piglets treated on day 1
`had a haemoglobin concentration (Hb) ±SD of 92 g litre–1 (±9) and 94 g litre–1 (±9), and the piglets treated on day 3 had a Hb of 81 g
`litre–1 (±7) and the one treated on day 4 had a Hb of 78 g litre–1 (±7) on day 7. On days 14 and 21 there were no differences between
`groups. This study indicates that some piglets were anaemic and responded to subcutanous iron injection on day 1.
`
`DOMESTIC piglets are born with very low iron reserves
`and receive too little iron from sows’ milk (Venn et al
`1947). Modern pig husbandry practices prevent contact
`with soil, the main source of iron for piglets in the wild.
`Pigs have been bred for high weight gain for many years,
`and this has also affected iron requirements in piglets. The
`Norwegian Landrace breed is a very fast growing breed
`with large litter size and high birth weight. The average
`weight on the day after birth in pure Norwegian Landrace
`and cross-bred Yorkshire piglets has been found to be
`between 1·5 and 1·9 kg in different studies. The average
`haemoglobin concentration (Hb) the day after birth has been
`found to be between 78 and 92 g litre–1 and average numbr
`of erythrocytes (RBC) between 3·7 and 4·5 x 109 litre–1 in
`these herds (Egeli and Framstad 1998a,b, Egeli et al
`1998c). This indicates that the Norwegian Landrace and
`crossbred Yorkshire piglets are born anaemic. If this
`anaemia is caused by iron deficiency, the piglets should be
`treated soon after birth. On the other hand possible detri-
`mental effects of high doses of iron to newborn piglets may
`not make it suitable to treat early in life especially if the
`piglets do not need, or are not able to utilise the iron admin-
`istered (Bollwahn et al 1972, Holmgren 1996, Egeli and
`Framstad 1998a).
`The aims of the study were to evaluate the effect on
`haematology of iron-dextran injection on the first, third or
`fourth day after birth in piglets with high birth weight and
`weight gain. An automatic blood analyser, Technicon H*1®
`(Bayer Instruments Corp., Tarrytown, NY, USA) which per-
`form complete blood cell counts and leukocyte differential
`counts, and is able to detect early changes in red cell sub-
`populations, was used in this study to evaluate haematological
`
`changes in the early postnatal period in piglets treated with
`iron on three different days.
`
`MATERIALS AND METHODS
`
`The study took place in a commercial herd which as kept
`under a good standard of health care and husbandry. All the
`investigations and treatments were performed by a veteri-
`narian. The litters were kept with the sows in farrowing
`crates on a concrete floor covered with sawdust. Two-thirds
`of the floor was solid but the area behind the sows was per-
`forated. The floor was scraped clean every day. The sows
`were fed commercial pelleted food and sour milk, but the
`piglets received only sow’s milk and no creep feed. The pigs
`were first to fifth litters, litter size to weaning ranged from
`nine to 13 piglets. The sows were free from sarcoptic man-
`age, routinely treated for gastrointestinal helminths, and
`vaccinated against porcine parvovirus, swine erysipelas and
`Escherichia coli infections. The piglets were treated prophy-
`toltrazuril (Baycox®: Kiel,
`lactically with 20 mg kg–1
`Germany) against coccidiosis on the fifth day after birth.
`The male piglets were not castrated during the study. The
`study was ethically discussed and found to follow the laws
`concerning research animals.
`
`Trial 1
`Forty-eight Norwegian Landrace x Yorkshire piglets from
`four litters were divided randomly into two groups (split
`litters). All piglets were individually tattooed with a number
`in the ear. The piglets in one group received 180 mg iron as
`
`0034-5288/99/030179 + 06 $18.00/0
`
`© 1999 W. B. Saunders Company Ltd
`
`Pharmacosmos, Exh. 1062, p. 1
`
`

`
`180
`
`A. K. Egeli, T. Framstad
`
`TABLE 1: Haematology during the preweaning period in Trial 1 (Mean ± SD). The piglets in T1D1 were injected with 180 mg iron as iron-dextran on day
`1 and the piglets in T1D4 on day 4
`
`Hb
`g litre–1
`RBC
`(x 1012 litre–1)
`MCV
`(fl)
`MCH
`(pg)
`MCHC
`(g litre–1)
`RDW (per cent)
`HDW (g litre–1)
`
`T1D1
`
`90
`(14)
`4·48
`(0·72)
`64·5
`(3·5)
`20·0
`(1·3)
`311
`(10)
`16·8
`31·7
`
`Day 1
`
`T1D4
`
`Day 4
`T1D1
`
`T1D4
`
`Day 7
`T1D1
`
`84
`(14)
`4·13
`(0·74)
`65·0
`(3·3)
`20·3
`(1·0)
`313
`(8)
`16·9
`32·5
`
`80
`(10)
`3·83
`(0·57)
`69·3
`(4·1)
`21·0
`(1·2)
`303
`(6)
`24·3
`30·7
`
`70b
`(9)
`3·59
`(0·56)
`64·0c
`(3·3)
`19·8b
`(1·6)
`308
`(15)
`18·7c
`33·9c
`
`94
`(9)
`4·29
`(0·62)
`73·7
`(5·5)
`22·0
`(1·4)
`299
`(9)
`22·2
`24·8
`
`T1D4
`
`78c
`(7)
`3·75b
`(0·51)
`69·6a
`(4·6)
`20·9a
`(1·3)
`301
`(8)
`27·3c
`29·5c
`
`Day 14
`T1D1
`
`T1D4
`
`Day 21
`T1D1
`T1D4
`
`103
`(8)
`4·79
`(0·60)
`67·9
`(5·5)
`21·5
`(1·5)
`317
`(10)
`18·1
`22·9
`
`103
`(7)
`4·77
`(0·56)
`68·5
`(5·3)
`21·7
`(1·6)
`317
`(9)
`20·2c
`24·6b
`
`103
`(9)
`5·52
`(0·50)
`61·4
`(4·3)
`18·7
`(1·6)
`305
`(8)
`18·2
`23·9
`
`103
`(12)
`5·49
`(0·64)
`60·7
`(5·4)
`18·9
`(2·0)
`310
`(9)
`20·1
`25·0
`
`SD in parenthesis. a = P<0·05, b = P<0·01, c = P<0·001 between groups
`
`colloidal ferri-dextran (Idofer®; St. Galen, Switzerland) by
`subcutaneous injection in the inguinal area 19-26 hours after
`birth (day 1). This group was designated T1D1 (trial 1,
`treated day 1). The piglets in the other group received iden-
`tical iron treatment on the fourth day after birth, this group
`being designated T1D4 (trial 1, treated day 4). All the piglets
`were weighed, and 1 ml blood collected using ethylenedi-
`aminetetra-acetic acid (EDTA) as an anticoagulant, using a
`method described previously (Framstad et al 1988), before
`treatment in the morning on day 1 and on days 4, 7, 14
`and 21. One sow suffered from mastitis-metritis-agalactia
`(MMA) and three of her piglets were raised by other sows.
`
`Trial 2
`
`Twenty piglets (two litters) were divided in two groups
`(split litters). One group of piglets was given 180 mg iron as
`colloidal ferri-dextran (Idofer®) by subcutaneous injection
`12–24 hours after birth (day 1), the group being designated
`T2D1 (trial 2, treated day 1). The piglets in the other group
`were given identical iron treatment on the third day after
`birth, this group being designated T2D3 (trial 2, treated day
`3). The piglets were weighed and 1 ml blood was collected
`as in trial 1 on days 1, 3, 7 and 14.
`An automated blood analyser; the Technicon H*1® (H*1)
`was used in this study. H*1 utilises the principles of auto-
`mated cytochemistry and laser light scatter in a flow cytome-
`ter to perform cell counts and leukocyte differential counts
`(Simson et al 1988). Erythrograms of the distribution of ery-
`throcyte size and haemoglobin concentration were also pre-
`sented visually by the H*1 for each piglet. The erythrocyte
`count (RBC), haemoglobin concentration (Hb), mean cell vol-
`ume (MCV), erythrocyte distribution width (i.e., coefficient of
`variation of the RBC volume histogram) (RDW) and haemoglo-
`bin distribution width (i.e. standard deviation of the haemo-
`globin concentration histogram) (HDW), as well as the number
`of leukocytes (WBC), neutrophilic granulocytes (NEUT), lym-
`phocytes (LYMP), monocytes (MONO), eosinophilic granulo-
`cytes (EOS), basophilic granulocytes (BASO) and large
`unstained cells (LUC), were measured by the H*1. The mean
`cell haemoglobin (MCH) and mean cell haemoglobin concen-
`tration (MCHC) were estimated by the H*1 from RBC and Hb in
`MCH and from RBC, Hb and MCV in MCHC. All samples taken
`on day 1 were analysed within four hours. A few samples
`
`taken on other days were stored for practical reasons in a
`refrigerator for 24 hours before analysis.
`Comparison of two means was performed using the t-test
`(Altman 1993). The development of haematological param-
`eters within groups was examined using a paired t-test.
`Relationships between the changes in MCV from day 1 to
`day 4 and Hb on day 1, and also between changes in MCV
`from day 4 to day 7 and Hb on day 4, were plotted and deter-
`mined in trial 1 using linear regression (Altman 1993).
`
`RESULTS
`
`Tables 1 and 2 show the development and differences
`between groups in haematological parameters in the two tri-
`als in the pre-weaning period. Hb and RBC counts decreased
`in both groups from day 1 to day 3 or 4 (P<0·001), and
`increased to the day 1 level in T1D1 and T2D1 on day 7.
`The piglets injected on day 3 or 4 had a lesser increase to
`day 7. MCV, MCH and RDW developed differently in the two
`groups from day 1 to day 3 or 4. As the new immature red
`cells are larger, there will be an increase in MCV and RDW
`when the production of new cells are high. With high
`haemoglobin production, MCH will also increase. In both tri-
`als the iron-treated piglets showed an increase in MCV and
`MCH and a higher increase in RDW than the untreated piglets
`from day 1 to day 3 or 4 (P<0·001). T2D3 and T1D4 piglets
`had an increase in MCV, MCH and RDW from day 3 or 4 to
`day 7 (P<0·001). HDW also showed a more rapid decrease in
`the piglets treated with iron on day 1 than the other groups.
`MCHC decreased from day 1 to day 7 in all groups
`(P<0·001). T1D1 piglets had higher Hb, MCH (P<0·01), MCV
`and RDW (P<0·001) than T1D4 piglets on day 4 and higher
`Hb (P<0·001), RBC (P<0·01), MCH and MCV (P<0·05) on day
`7. T2D1 piglets had higher MCV, MCH and RDW than T2D3
`piglets on day 3 (P<0·05), and higher Hb and RBC on day 7
`(P<0·05). RDW was in T1D1 piglets lower than in T1D4
`piglets on day 7 and day 14 (P<0·001), and HDW was lower
`on days 4, 7 (P<0·001) and 14 (P≤0·01). T2D1 piglets had
`lower RDW than T2D3 piglets on day 7 (P<0·01), and lower
`HDW on day 3 (P<0·01) and day 7 (P<0·05). In T1 Hb, RDW
`and HDW were of the same order of magnitude on day 14
`and day 21. MCV, MCH and MCHC decreased from day 14 to
`day 21 (P<0·05–P<0·001).
`
`Pharmacosmos, Exh. 1062, p. 2
`
`

`
`Iron-dextran supplementation in piglets
`
`181
`
`TABLE 2: Haematology during the preweaning period in Trial 2 (Mean ± SD). The piglets in T2D1 were injected
`with 180 mg iron as iron-dextran on Day 1 and the piglets in T2D3 on day 3
`
`Day 1
`T2D1
`T2D3
`
`Day 3
`T2D1
`T2D3
`
`Day 7
`T2D1
`T2D3
`
`Day 14
`T2D1
`T2D3
`
`Hb
`(g litre–1)
`RBC
`(x 1012 litre–1)
`MCV
`(fl)
`MCH
`(pg)
`MCHC
`(g litre–1)
`RDW (per cent)
`HDW (g litre–1)
`
`93
`(24)
`4·21
`(0·97)
`72·0
`(3·7)
`21·9
`(1·0)
`305
`(7)
`17·7
`31·2
`
`88
`(16)
`4·04
`(0·70)
`71·1
`(1·9)
`21·9
`(0·5)
`308
`(8)
`17·0
`32·0
`
`82
`(16)
`3·73
`(0·74)
`74·1
`4·0)
`22·1
`(1·0)
`298
`(9)
`22·3
`27·7
`
`72
`(11)
`3·39
`(0·48)
`69·9a
`(1·5)
`21·1a
`(0·7)
`301
`(6)
`18·2a
`30·9b
`
`92
`(9)
`4·07
`(0·45)
`79·0
`(7·3)
`22·7
`(1·7)
`288
`(9)
`23·7
`27·0
`
`81a
`(7)
`3·62a
`(0·24)
`79·2
`(1·9)
`22·4
`(0·7)
`283
`(6)
`28·6b
`29·5a
`
`109
`(13)
`5·02
`(0·54)
`71·2
`(2·0)
`21·7
`(0·8)
`305
`(10)
`19·1
`22·7
`
`103
`(8)
`4·74
`(0·29)
`72·3
`(3·1)
`21·7
`(0·8)
`301
`(9)
`20·8
`23·6
`
`SD in parenthesis, a = P<0·05, b = P<0·01, c = P<0·001 between groups
`
`in Trial 1
`the preweaning period
`in absolute numbers during
`and differential counts
`TABLE 3: WBC
`(Mean ± SD). The piglets in T1D1 were injected with 180 mg iron as iron-dextran on day 1 and the piglets in T1D4 on day 4
`
`WBC
`(x 109 litre–1)
`
`Day 1
`T1D1
`T1D4
`
`Day 4
`T1D1
`T1D4
`
`Day 7
`T1D1
`T1D4
`
`Day 14
`T1D1
`T1D4
`
`Day 21
`T1D1
`
`T1D4
`
`WBC
`
`NEUT
`
`LYMP
`
`MONO
`
`EOS
`
`BASO
`
`LUC
`
`9·3
`(2·4)
`6·8
`(2·1)
`2·0
`(0·4)
`0·21
`(0·08)
`0·12
`(0·06)
`0·01
`(0·01)
`0·19
`(0·09)
`
`7·6a
`(1·7)
`5·1b
`(1·5)
`1·9
`(0·6)
`0·17
`(0·06)
`0·12
`(0·06)
`0·01
`(0·01)
`0·18
`(0·13)
`
`11·1
`(3·8)
`6·6
`(3·0)
`3·5
`(1·3)
`0·35
`(0·15)
`0·23
`(0·17)
`0·03
`(0·02)
`0·27
`(0·12)
`
`9·3
`(2·8)
`4·8a
`(2·4)
`3·7
`(1·2)
`0·32
`(0·17)
`0·17
`(0·11)
`0·03
`(0·02)
`0·25
`(0·11)
`
`11·2
`(2·6)
`5·9
`(1·7)
`4·5
`(1·2)
`0·28
`(0·11)
`0·19
`(0·13)
`0·04
`(0·02)
`0·31
`(0·17)
`
`12·1
`(3·3)
`6·2
`(2·9)
`5·1
`(1·4)
`0·33
`(0·12)
`0·16
`(0·11)
`0·04
`(0·03)
`0·31
`(0·15)
`
`8·1
`(4·1)
`3·0
`(1·7)
`4·3
`(2·7)
`0·19
`(0·10)
`0·08
`(0·05)
`0·05
`(0·09)
`0·18
`(0·12)
`
`7·0
`(2·0)
`2·3
`(0·9)
`4·2
`(1·3)
`0·15
`(0·06)
`0·14
`(0·15)
`0·04
`(0·05)
`0·15
`(0·07)
`
`15·7
`(4·2)
`3·9
`(1·2)
`10·7
`(3·2)
`0·42
`(0·13)
`0·14
`(0·11)
`0·09
`(0·04)
`0·56
`(0·18)
`
`15·4
`(2·9)
`4·0
`(1·7)
`10·2
`(1·8)
`0·40
`(0·10)
`0·12
`(0·11)
`0·08
`(0·04)
`0·52
`(0·15)
`
`SD in parenthesis. a = P<0·05, b = P<0·01, c = P<0·001 between groups
`
`Clinically, the piglets in T1D4 were observed to be paler
`than the piglets in T1D1 on day 4.
`The development in total white cell counts (WBC) and the
`results from the differential counts in Trail 1 are shown in
`Table 3. WBC increased from day 1 to day 7 (P<0·05 in
`T1D1, and P<0·001 in T1D4). Values in both groups
`decreased from day 7 to day 14 (P<0·01) and increased from
`day 14 to day 21 (P<0·001). There was a difference between
`groups in WBC (P<0·05) and NEUT (P<0·01) on day 1 with
`the highest values in T1D1. The difference in NEUT was still
`present on day 4 (P<0·05). Changes in WBC in trial 2 fol-
`lowed the same main pattern as in trial 1. Values were of the
`same order of magnitude, and there were no differences
`between groups.
`Fig 1 shows the plots and linear regression of the relation-
`ship between Hb on day 1 and the changes in MCV from day
`1 to day 4 in T1D1 (Fig 1a) and in T1D4 (Fig 1b). It also
`shows the relationship between Hb on day 4 and the changes
`in MCV from day 4 to day 7 in T1D1 (Fig 1c) and T1D4 (Fig
`1d). While MCV increase with production of new immature
`cells, Fig 1(a and d) shows that the piglets with the lowest
`initial Hb produced more new cells than the piglets with
`highest initial Hb after they had received iron on day 1 (Fig
`1a) or day 4 (Fig 1d). Fig 1(c) show that the piglets treated
`with iron on day 1, and which had the lowest Hb on day 4,
`also had higher increase in MCV from day 4 to 7, than the
`
`piglets with highest Hb on day 4. Iron deficiency lead to a
`production of microcytic cells. Fig 1(b) shows that the
`untreated piglets with lowest initial Hb produced more
`microcytic cells from day 1 to day 4 than the untreated
`piglets with highest initial Hb levels.
`Average bodyweight in T1D1 and in T1D4 were, respec-
`tively, 1·79 and 1·77 kg on day 1, 3·05 and 2·98 kg on day 7,
`5·23 and 5·16 kg on day 14, and 7·15 and 6·95 kg on day 21.
`The corresponding figures for T2D1 and T2D3 were,
`respectively, 2·0 and 1·87 kg on day 1, 3·43 and 3·25 kg on
`day 7, and 5·80 and 6·21 kg on day 14.
`Seven piglets (four in T1D1 and three in T1D4) were
`treated for arthritis or infected wounds, and were excluded
`from the study. One blood sample taken on day 7 was
`excluded because of coagulation, as were two differential
`leukocyte counts on day 14 because of analytical problems.
`Three piglets in T2D1 and one piglet in T2D3 were
`treated for arthritis and two piglets in T2D3 died, and all six
`were excluded from the study. One piglet in T2D3 was ill on
`day 14, and results for this piglet on this day were excluded.
`
`DISCUSSION
`
`In a former study the precision of the H*1 and the
`effect of one and two days of storage in a refrigerator were
`
`Pharmacosmos, Exh. 1062, p. 3
`
`

`
`182
`
`A. K. Egeli, T. Framstad
`
`y = 0·054x – 5·65
`r = 0·57
`P < 0·01
`
`60
`
`70
`
`80
`90
`100
`Hb (g litre–1) day 1
`
`110
`
`120
`
`y = –0·230x + 21·90
`r = –0·59
`P < 0·01
`
`(b)
`
`14
`12
`10
`
`8 6 2 0
`
`4
`
`–2
`–4
`50
`
`(d)
`
`14
`12
`10
`
`8 6 2 0
`
`4
`
`–2
`50
`
`60
`
`70
`
`80
`90
`100
`Hb (g litre–1) day 1
`
`110
`
`120
`
`MCV (fl) (day 4 – day 1)
`
`MCV (fl) (day 7 – day 4)
`
`y = –0·116x + 15·11
`r = –0·56
`P = 0·01
`
`(a)
`
`14
`12
`10
`
`8 6 2
`
`4
`
`0
`50
`
`60
`
`70
`
`100
`80
`90
`Hb (g litre–1) day 1
`
`110
`
`120
`
`y = –0·238x + 23·40
`r = –0·80
`P < 0·001
`
`(c)
`
`14
`12
`10
`
`8 6 2
`
`4
`
`0
`50
`
`60
`
`70
`
`80
`90
`100
`Hb (g litre–1) day 1
`
`110
`
`120
`
`MCV (fl) (day 4 – day 1)
`
`MCV (fl) (day 7 – day 4)
`
`FIG 1: (a-d): Changes in MCV between the first (day 1) and the fourth day after birth (day 4) plotted against Hb level on day 1 in Group T1D1 (Fig 1a) and Group
`T1D4 (Fig 1b), and also changes in MCV between day 4 and day 7 plotted against Hb levels on day 4 in group T1D1 (Fig 1c) and Group T1D4 (Fig 1d). The piglets
`in T1D1 were injected with 180 mg iron as iron-dextran on day 1 and the piglets in T1D4 on day 4
`
`evaluated in one- and 14-day-old piglets (Egeli et al 1998d).
`In that study the differential counts determined automati-
`cally were also compared with microscopic manual differ-
`ential counts. In a group of 20 piglets the average values
`without and after one and two days of storage were very
`consistent (Egeli et al 1998d). There was also a high correla-
`tion between the automatic and manual differential counts
`for netrophils and lymphocytes in one- and 14-day-old
`piglets (r=0·85–0·93), and the average values between the
`two methods in all white cell types were almost the same.
`The H*1 counts thousands of cells compared with only 100-
`200 in manual microscopic counts and is thereby more reli-
`able (Davies and Fisher 1991). The H*1 report provided a
`lot of information on each piglet and was quite appropriate
`to evaluate erythropoiesis, anaemia, and changes in leuko-
`cyte number and differential counts in piglets.
`Many of the piglets in this study had low Hb on day 1 and
`must be considered to have been anaemic at birth (Fig 1a and
`b). The low Hb on day 1 could have been due to an iron defi-
`ciency anaemia. In adults, iron deficiency anaemia is easily
`diagnosed as a microcytic hypochromic anaemia (Jain 1986).
`In newborn piglets, differences between piglets in plasma
`expansion and hydration could affect Hb and RBC on day 1
`(Egeli and Framstad 1998a). MCV, MCH, MCHC, RDW and
`HDW at birth are also difficult to evaluate because of immatu-
`rity of the cells. Both Hb and RBC can be expected to decrease
`from birth to day 4 due to plasma expansion and the rapid
`growth of the piglets, irrespective of iron treatment
`(Bollwahn et al 1972, Furugouri 1975, Egeli and Framstad
`1998a). Such an anaemia is considered to be physiological.
`Changes in RDW or MCV could be used to describe erythro-
`poietic activity in the first week. The MCV value is probably
`
`the most suitable, because it will increase with the produc-
`tion of more macrocytic cells and decrease with the presence
`of more microcytic cells, while RDW will increase with
`increasing numbers of both cell types. From Table 1, it can be
`seen that MCV values were nearly the same on day 1 and day
`4 in untreated piglets. If the piglets with lowest Hb on day 1
`had an iron deficiency anaemia, MCV would be expected to
`decrease in these untreated piglets on day 4 because of pro-
`duction of microcytic cells. This was confirmed to be the
`case, as seen in Fig 1b, by the significant positive correlation
`between Hb level on day 1 and the changes in MCV from day
`1 to day 4, showing, that untreated piglets with low Hb on day
`1 produced microcytic erythrocytes.
`A delay in the utilisation of iron in injected newborn
`piglets may mean that there is no advantage injecting iron-
`dextran very early after birth, since Vrigazov and Dilov
`(1976) could not detect labelled iron from iron-dextran in
`the erythrocytes of piglets until 24 hours after injection, and
`Braude et al (1962) found that orally-administered inorganic
`iron was available for haemoglobin synthesis more rapidly
`than iron from injected iron-dextran. The explanation for
`this could be that iron-dextran needs to undergo ‘reticulo-
`endothelial digestion’ before the iron is available for incor-
`poration into transferrin (Morgan and Finch 1966, Kornfeld
`et al 1969). Furugouri (1975) found that transport protein
`levels and iron-binding-capacity were very low in newborn
`piglets even when erythropoietic activity seemed to be high.
`Bollwahn et al (1972) found no difference between groups
`in Hb, RBC and packed cell volume on day 7 when piglets
`were injected on day 3 or immediately after birth. This was
`explained by immaturity of liver function in the first days of
`life. These findings are not in accordance with those in the
`
`Pharmacosmos, Exh. 1062, p. 4
`
`

`
`Iron-dextran supplementation in piglets
`
`183
`
`present study, in which piglets treated on day 1 were still
`ahead on day 7 compared with the piglets treated on day 3 or
`day 4 (Tables 1 and 2). In trial 1, the observed differences
`between groups with regard to Hb, MCV, MCH, RDW and HDW
`on day 4, showed that the production of haemoglobin and
`erythrocytes were both higher in the group injected with
`iron-dextran on day 1 than in the untreated group T1D4. In
`trial 2 on day 3, the piglets that had been injected with iron-
`dextran two days earlier had higher MCV, MCH and RDW, but
`lower HDW than the untreated piglets T2D3. Some of these
`piglets were only two-and-a-half-days old. The present
`study indicates that piglets are able to synthesise haemoglo-
`bin from day 1, and respond quickly to iron-dextran injec-
`tions. An explanation could be that the piglets in the present
`trial were heavier than those in most of the previously
`reported studies dealing with erythropoiesis in newborn
`piglets. Moreover, the piglets in Bollwahn’s study was
`delivered by caesarean section, which might have interfered
`with maturity development and affected haematological
`parameters in the piglets. Thorén-Tolling (1975) found that
`iron stores in the liver were proportional to birth weight.
`Large litter size coupled with high birth weight of the
`piglets, increases the demands for iron transfer from the sow
`to the foetuses. The higher erythropoietic activity found on
`day 3 in the present study in a two-and-half-day old piglet
`injected with iron-dextran two days earlier, than in an
`untreated piglet, indicate that the demand for additional iron
`supply and already arisen. This might also explain the rapid
`reaction after iron supplementation.
`From Tables 1 and 2, it can be seen that MCV increased
`from day 1 to day 7 and RDW from day 1 to day 4 in the
`piglets injected with iron-dextran on day 1. There was a sig-
`nificant negative correlation between Hb on day 1 and the
`increase in MCV from day 1 to day 4, in piglets given iron
`treatment on day 1 (Fig 1a). These findings strongly indicate
`a higher erythropoietic activity in the iron-treated piglets
`with the lowest Hb on day 1. The piglets with highest Hb did
`not respond as well to iron treatment. This also indicates that
`iron deficiency anaemia already existed in some piglets on
`day 1. Looking at Fig 1(a) and (d) the main changes in MCV
`seen in T1D4 between day 4 and 7 were the same as those
`seen between day 1 and 4 in T1D1. In orally iron-treated
`piglets, absorption of iron is regulated in relation to body
`iron stores and erythropoietic activity (Bothwell et al 1958).
`The injection of iron disturbs this regulation mechanism,
`and iron is available in excess. The results presented here
`indicate that intestinal absorption of iron is not the only
`important factor regulating haemoglobin production in new-
`born piglets. In older piglets, oxygen tension and Hb regulate
`erythropoietin production (Sjaastad et al 1992). Iron has
`been found not only to be a building block in haemoglobin
`production, but also a stimulus for erythropoietin synthesis
`in anaemic piglets (Sjaastad et al 1996). In iron-treated new-
`born piglets, erythropoietin was found to increase during the
`first day of life and then decrease over the next three days
`(Sjaastad et al 1992). In the present study, the reason why,
`the piglets with the lowest Hb on day 1, which also had
`access to iron (i.e. received iron treatment), showed the
`highest erythropoetic activity, might be that erythropoietin
`production was stimulated more markedly in these piglets.
`As shown in Table 1, the highest HDW value was found on
`day 1. This might be a reflection of the situation in the
`
`piglets before birth. While HDW decreased from day 1 in the
`piglets injected with iron-dextran at that time, it first
`decreased from day 3 or day 4 in the piglets injected on
`those respective days. HDW seemed to be a more sensitive
`parameter than MCHC in detecting erythropoietic activity in
`the first week after birth. Although MCHC decreased from
`day 1 to day 7, there was no difference between groups.
`Both MCV and RDW have previously been found to be sensi-
`tive indicators of active erythropoiesis in piglets (Holter et
`al 1991, Egeli and Framstad 1998a).
`On days 14 and 21, there were no differences between
`groups in RBC, Hb, MCV, MCH and MCHC. In trial 1, average
`Hb, RDW, and HDW within groups were the same on days 14
`and 21, but MCV, MCH and MCHC decreased from day 14 to
`day 21. About 40 mg iron needs to be absorbed per 1 kg
`weight gain if Hb is to be maintained at 100 g/litre–1. On this
`basis the amount of iron injected into the piglets in the pres-
`ent trial would have covered their iron requirements for
`about two weeks. This corresponds well with the blood val-
`ues found, which indicated a slowing down in production of
`haemoglobin from about day 14, presumably due to deple-
`tion of iron reserves.
`The changes in WBC and differential counts (Table 3)
`largely correspond with the development in white cell popu-
`lations described by Jain (1986) and Imlah and McTaggart
`(1977). The increase in lymphocytes and thereby WBC found
`on day 21 in the present study, seems, however, to have
`occurred earlier than previously described in the available lit-
`erature. The high neutrophil counts at birth can be explained
`by the high cortisone level at that time (Brenner and Gürtler
`1977). Some authors found elevated WBC and neutrophil
`counts in piglets in response to iron treatment compared with
`those in untreated piglets, or in piglets treated with smaller
`amounts of iron (Kay et al 1980, Furugouri et al 1983).
`Bacterial challenge together with access to iron could have
`caused the increase in WBC in the iron-treated piglets in the
`mentioned studies. Iron deficiency or access to iron might
`also interfere with WBC production. In humans and rats,
`myeloperoxidase activity and the ability of neutrophils to kill
`bacteria were found to be impaired in iron deficiency
`anaemia (Dallman 1986). The neutrophil count was found to
`decrease in anaemic piglets compared with iron-treated ani-
`mals (Gainer et al 1985). The results in the present study are
`confused by the significant difference found between group
`in WBC and neutrophiles on day 1. However, by day 7, the
`difference had diminished. The results indicate that access to
`iron from day 1 does not stimulate the production of leuko-
`cytes or neutrophiles compared with iron injection on day 4.
`The values for WBC found in the present study on day 4 were
`lower than those found in the iron-treated piglets in the study
`of Kay et al (1980) and Furugouri et al (1983).
`
`CONCLUSION
`
`Some piglets already suffered from an iron deficiency
`anaemia on day 1 and responded quickly to subcutaneous
`iron-dextran injections. The piglets treated on day 1 were
`still ahead on day 7 compared with the piglets treated on day
`3 or 4. Differences between groups were beginning to
`develop on day 3, but were highest on day 7. The production
`of erythrocytes was highest after iron treatment in the
`
`Pharmacosmos, Exh. 1062, p. 5
`
`

`
`184
`
`A. K. Egeli, T. Framstad
`
`piglets with lowest haemoglobin concentrations levels ini-
`tially. The white cell count were not affected whether iron
`was injected on day 1, 3 or 4.
`
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