A further study of the effects of feeding 45 per cent dried poultry battery waste on the health of lambs

J. COMP.

PATH.

1981.

VOL.

A FURTHER 45 PER CENT

91

545

STUDY OF THE EFFECTS DRIED POULTRY BATTERY THE HEALTH OF LAMBS

OF

FEEDING WASTE ON

BY

N. F. Moredun

K. W. ANGUS

SUTTLE,

Research Institute,

408 Gilmerton

and A. C.

Road, Edinburgh

EH17

FIELD 7JH,

U.K.

INTRODUCTION

In a previous experiment the inclusion of 45 to 60 per cent dried battery waste in the diet of young lambs caused anorexia, hypoalbuminaemia, ascites and centrilobular necrosis and fibrosis of the liver after 8 weeks (Angus, Suttle,

Munro and Field, 1978). The hepatotoxic principle was not identified but its effects resembled those of nitrosamine poisoning in sheep (Koppang, 1964; Hansen, 1964). The absence of such a syndrome in many previous experiments in which battery waste was included in the diet of ruminants (for reviews see Smith, 1974; Blair and Knight, 1973) raised the possibility that the toxic principle may not be a common constituent of these by-products. We therefore

obtained battery wastes from two additional sources and compared their effects on the health of lambs with those of the waste used in our original experiment. In addition to the liver, the kidney and thyroid were selected for close examination because previous studies had shown that broiler waste had nephrotoxic properties (Angus et al., 1978) and an unclassified waste had thyrotoxic properties (Neuman, Nobel and Bogin, 1977) when included in the diets of sheep. MATERIALS

AND

METHODS

Animals and diets. Eighteen Cheviot lambs, aged between 16 and 18 weeks, were stratified according to initial live weight (23.1 f 2.9 kg) and allocated at random within strata to one of 3 battery waste groups (F, G and H, Table 1). Each group received for 87 days a barley-based diet containing 45 per cent battery waste as described by Angus et al. (1978) except that the waste came from one of 3 sources.

Group F received the same artificially

dried battery waste as that used by Angus

et al. (1978), Group G received a naturally

dried battery waste obtained from Gleadthorpe Experimental Husbandry Farm, and Group H received an artificially dried waste obtained from Home Farm, Langleybury, Herts. The lambs were housed in groups of 6 and received their diets and tap water ad libitum. Food refusalswere collected daily and weighed at weekly intervals and the animals were also weighed each week. Analyses. Blood samples were taken every 14 days from the fourth week of the experiment onwards for the determination of haemoglobin, plasma protein and aspartate amino transferase (AAT) activity. At slaughter, additional blood samples were taken for the determination of plasma albumin and gamma glutamyl transferase estimations (yGT) : the latter was included asa more specific indicator of liver damage than AAT. The analytical methods for plasma samplesand the battery wasteswere 0021-9975/81/040545+07

$02.00/O

0 1981 Academic

Press Inc.

(London)

Limited

546

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SUTTLE

et

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generally those described by Angus et al. (1978) and Suttle, Munro and Field (1978). In addition, the yGT estimations followed the method of Szasz (1969). Gross energy contents of the wastes were determined by bomb calorimetry and their steam volatile nitrosamine contents by resolution mass spectrometry. The EDTA-extracted Cu in the wastes was estimated by the method of Suttle and Price (1976). The gut, including contents, liver and heart were removed from the carcase at slaughter and the organs and carcase were then weighed. Samples of liver, kidney, gut and mesenteric lymph nodes were removed for biochemical and histological examination following procedures described by Angus et al. (1978). Samples of spleen, thyroid, aorta and pancreas were also taken and fixed and processed by the methods used for the other soft tissues. RESULTS

ChemicalCompositionof Battery Wastes The 3 battery wastes differed considerably (Table 1). Waste H had an unusually high waste G had a lower gross energy and higher

in their chemical composition ash and low uric acid content, ash content than F and differed

from both artificially dried wastes (F and H) in having less than 10 pg per kg DM of N-nitrosodimethylamine. Although the Cu concentrations in each waste were of the same order a much smaller fraction of the total Cu was extracted by EDTA from waste H (0.22) than from wastes F (0.64) and G (0.64). ‘TABLE CHEMICAL

COMPOSITION

OF

3

BATTERY

WASTES

1 USED

IN FEEDING

TRIALS

WITH

LAMBS

cu

energy (cal per g)

Xitrogen (par cent)

Uric acid (per cent)

3151 2934 2956 -

4.40 5.18 3.18 4.6

6.1 6.0 1.1 6.3

Gross SOUrGe*

F (Feedpac) G (Gleadthorpe) H (Home-farm) Blair and Knight * For

details

(1973)

Ash (per cent) 24.4 31.0 36.9 26.5

ED TA Total extractable (mg per kg DM) 50.5 42.0 54.6 61

N-nitrosodimethylamine (pg per kg DM);

32.3 26.9 12.0 -

<

114 10 82 -

see text.

Food Consumptionand Liveweight Gain The 3 groups of lambs showed different patterns of food consumption [Fig. 1 (a)].

The

mean

daily

food

intake

on waste

F reached

a maximum

of 1 kg

per day after only 2 weeks, whereas consumption of wastes G and H increased steadily for 7 weeks, reaching plateaux of approximately 1.45 and 2.11 kg per day, respectively .The total food consumption during the experiment was 84, 107 and 163.6 kg on the diets containing wastes F, G and H, respectively. The corresponding mean daily weight gains, O-04, 0.089 and 0.055 kg per day were not significantly different, but the group given waste F ceased growing after about 7 weeks [Fig. 1 (b)]. The feed conversion efficiencies of Groups F, G and H were 21.5, 13.7 and 34.1 kg feed per kg weight gain, respectively. Organ Weights The effects of source of battery waste on the mean fresh weight of the carcase and of the liver, heart and gut-contents expressed as a percentage of car-case

LAMBS

FED

BATTERY

547

WASTE

(b)

0

,

,

,

,

,

2

4

6

6

IO

IL

I2

14

Time (weeks)

Fig.

1. Mean daily food consumption (a) and liveweight (b) of lambs given diets containing 45 per cent battery waste from one of three sources, described in the text and given code letters F(A), G(O) and H(O).

weight are shown in Table 2. Carcase weight tended to be lower in the lambs given waste F than in the other groups. The gut plus contents was heaviest in relation to carcase weight in Group F (P < 0.001) and liver weight showed a similar trend. Heart weight, however, was unaffected by the treatments. TABLE MEAN

FRESH

CARCASE WT GIVEN A DIET

(KG) AND CONTAINING

ORGAN

45

2

WTS AS A PERCENTAGE OF CARCASE WT IN GROUPS PER CENT BATTERY WASTE FROM ONE OF 3 SOURCES

OF LAMBS

S.E.of SOW&+ Carcase wt Liver wt Heart wt Gut and contents * For

details

wt > see text.

As percentage of carcase wt

F

G

H

18.5 2.89 0.77 42.1

22.1 2.30 0.76 33.3

21.2 2-18 0.74 32.2

d$j%ence between means & f & f

1.44 0.30 0.05 2.8

548

N.

F.

SUTTLE

et al.

Pathology Although no clinical evidence of abnormalities such as ascites was seen, all but one of the lambs given waste F showed slight to moderate centrilobular congestion and increased reticulin formation in the liver, as described by Angus et al. (1978) : none of the lambs given wastes G or H showed these lesions. By contrast all but one of the lambs given battery wastes G and H showed renal changes ranging from focal to widespread interstitial nephritis of the type described in lambs given broiler waste by Angus et al. (1978) : none of the lambs given waste F were affected in this way. The other soft tissues examined showed little or no sign of abnormality in any of the lambs. Biochemistry The results of biochemical measurements made during the experiment are summarized in Table 3. Plasma protein concentrations were lower in group F than in group H (P -=cO-05) and lower in group H than in group G (P < O-05) ; the differences were present throughout the 8-week period of observation. Haemoglobin values tended to be highest and plasma AAT values lowest in the lambs given waste G but the values were not significantly different from those of other groups. TABLE MEAN TAKEN

VALUES EVERY

FOR

14

3

PLASMA PROTEIN AND ASPARTATE AMINO TRANSFERASE AND HAEMOGLOBIN IN SAMPLES BETWEEN WEEKS 4 AND 12 FROM LAMBS WHICH RECEIVED DIETS CONTAINING 45 PER CENT BATTERY WASTE FROM ONE OF 3 SOURCES

DAYS

S.E. Source

*

Plasma protein (g per 1) Haemoglobin (g per 1) Plasma aspartate amino transferase (iu per 1) * For details

Of

F

G

H

dajkm between means

69.7 90.9

80.5 98.6

74.6 93.8

* 2.17 5 4.31

45.3

42.6

46.0

*

5.92

see text.

The results of biochemical measurements made at the end of the experiment are given in Table 4. Plasma albumin values were lower in group F than in Group H (P < 0.05) and in Group G (P < O-1). Within Group F, those animals with the lowest plasma albumin values (x: g per 1) had the highest gut plus contents : carcase weight ratios (y : kg per kg). The relationship was described by the equation Y = 0*53 - 0.00375~ + 0*00179: r = 0.77, 4 d.f. Values for yGT and liver Cu showed heterogeneity of variance. The animal with the most severe liver damage in Group F had a yGT activity of 217.4 which was far higher than any other values. Liver Cu values were subjected to logarithmic transformation and found to be far lower in Group H than in the other groups (P < 0.001).

LAMBS

FED

BATTERY TABLE

MEAN VALUES FOR LIVER &I, PLASMA ALBUMIN GROUPS OF LAMBS GIVEN DIETS CONTAINING

45

549

WASTE

4

AND y GLUTAMYL TRANSFERASE @CT) CONCENTRATIONS PER CENT BATTERY WASTE FROM ONE OF 3 SOURCES 12 WEEKS S.E.

y GT (iu per 1) Plasma albumin (g per 1) Liver Cu (mg per kg DM) * For details see text. t Mean excludes one value $ S.E. of mean.

IN FOR

Of

F

G

H

dz&ence between me0n.s

40.9t 28.0 328 & 24::

41.5 33.6 359 & 33

44.6 31.5 40 * 9

& 2.3 * 1.94 -

of 2 17.4.

DISCUSSION

The experiment shows that the hepatotoxic properties of the artificially dried battery waste F were not shared by a naturally dried waste (G) or another artificially dried waste (H) : the latter did, however, share with waste F the property of inducing hypoproteinaemia. It has been suggested that a nitrosamine might be the toxic principle in waste F (Angus et al., 1978) and it is interesting to note that steam-volatile nitrosamines were not detected in the innocuous naturally dried waste G. The variability in hepatotoxicity of battery wastes may be related to the extent to which storage or drying conditions favour the formation of nitrosamines or their precursors. Waste F was less hepatotoxic in this experiment than in our earlier study (Angus et al., 1978), as judged by the absence of ascites and the milder hypoalbuminaemia (2.8 g per 1 after 12 weeks versus 2.2 g per 1 after 10 weeks). The difference may reflect the fact that the lambs were less susceptible to the toxic factor by virtue of their genotype (Cheviot v. Scottish Blackface) or their more mature state at the start of the experiment (age 4 and 2 months and initial liveweight 23.1 v. 13.6 kg) or that the waste had become less toxic during the year-long period of storage between experiments. The prevalence of nephritis in Groups G and H given battery waste contrasts with the observations of our first experiment in which nephritis was only seen in lambs given broiler waste. The absence of renal damage in Group F may have been due to the lower intake of battery waste by these lambs. We found no evidence of C-cell (thyroid) hyperplasia or soft tissue calcification as reported by Neumann et al., 1977) in a Merino flock given a diet of poultry waste and straw for 2 years. It is possible that the nephrotoxic properties of diets containing high levels of battery waste may be of wider practical importance than either their hepatotoxic or thyrotoxic properties. The differences in food consumption between groups were large and are not readily explained in terms of the chemical composition of the battery wastes. The plateau in consumption of the diet containing waste F occurred much earlier in this experiment than in the previous one and growth rate was consequently poorer: it may have served as a defence mechanism, associated with either an increase in gut fill or hypertrophy of the alimentary tract. The high consumption of the diet containing waste H was not accompanied by an

550

N.

F.

SUTTLE

et

cd.

improvement in liveweight gain and must have been associated with a low digestibility or metabolizability of nutrients. One possible explanation is that the high ash (i.e. mineral) intake of waste H influenced the rate of digestion in the rumen (Wheeler, 1979; Rogers, Marks, Davis and Clark, 1979). The absorbability of Cu in battery wastes may also vary from source to source. Final liver Cu concentrations in lambs from Groups F and G approached those of the equivalent group in the first experiment (Suttle et al., 1978) in which 4.5 per cent of the ingested Cu was estimated to have been retained in the liver. Although waste H contained more Cu than the other wastes (Table l), very low Cu concentrations were found in this group, indicating that far lessof the Cu in that waste was absorbed. The EDTA-extractable Cu fraction in waste H was also small and EDTA extraction may therefore provide a useful technique for assessingthe potential Cu toxicity of a given poultry waste. It would, however, appear that battery wastes can be included in sheep diets in large amounts for long periods before liver Cu concentrations reach those associated with toxicity. SUMMARY

Although hepatotoxic properties of an artificially dried poultry waste (F) were detected when it was included as 45 per cent of a barley-based ration for lambs, they were lessmarked than in a previous study and were not found with another artificially dried waste (H) or a naturally dried waste (G). Wastes G and H both caused an interstitial nephritis which was not a feature of lambs given waste F. Food consumption was high and the risk of Cu toxicity was low on waste H but growth was poor. Possible explanations for variations in the clinical biochemical and production responsesof lambs to the inclusion of battery waste in their diets are discussed. ACKNOWLEDGMENTS

We are indebted to D. M. Pollock for preparing the diets, A. Anderson for tending the sheepand Miss E. Valente for completing most of the analyses.Additional information on the chemical composition of the poultry wasteswas kindly provided by R. Foxton of the ARC Poultry Research Centre, Edinburgh (grossenergy and uric acid) and R. L. S. Patterson of the ARC Meat Research Institute, Bristol (volatile nitrosamines). M. McLauchlan gave valued assistancein the statistical analysis of the data. We are also grateful to P. J. Hearn and his colleaguesat Gleadthorpe EHF, Mansfield for the supply of naturally dried battery waste. REFERENCES

Angus, K. W., Suttle, N. F., Munro, C. S., and Field, A. C. (1978). Adverse effects on health of including high levels of dried poultry waste in the diet of lambs. Journal of Comfiarative Pathology, 88, 449466. Blair, R., and Knight, D. W, (1973). Recycling animal wastes.Feedrtufi, 45, 32-36. Hansen, M. A. (1964). An outbreak of toxic liver injury in ruminants. Nordisk Veterinar-Medecin, 16, 323-342. Koppang, N. (1964). A previously unknown liver diseasein ruminants. Nor&k Veterinar-Medecin, 16, 305-322.

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WASTE

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Neumann, F., Nobel, T. A., and Bogin, E. (1977). Enzootic calcinosis in sheep and C-cells hyperplasia of the thyroid. Veterinary Record, 101, 364-366. Rogers, J. A., Marks, B. C., Davis, C. L., and Clark, J. H. (1979). Alteration of rumen fermentation in steers by increasing rumen fluid dilution rate with mineral salts. Journal cf Dairy Science, 62, 1599-l 605. Smith, L. W. (1974). Dehydrated poultry excreta as a crude protein supplement for ruminants. World Animal Review, 11, 6-11. Suttle, N. F., Munro, C. S., and Field, A. C. (1978). The accumulation of copper in the liver of lambs on diets containing dried poultry waste. Animal Production, 26, 39-45. Suttle, N. F., and Price, J. (1976). The potential toxicity of copper-rich animal excreta to sheep. Animal Production, 23, 233-241. Szasz, G. (1969). Kinetic photometric method for serum y-glutamyl transpeptidase. Clinical ChemistTy, 15, 124-I 36. Wheeler, W. E. (1979). Influence of cement kiln dust on reticular-rumen parameters of beef steers fed complete diets. Journal of Animal Science, 49, 1364-l 370. [Received for publication,

September lst, 19801