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Journal of Equine Veterinary Science 34 (2014) 88

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Journal of Equine Veterinary Science

journal homepage: www.j -evs.com

The effect of feeding FiberProtect� on stallion spermmorphology

N.L. Stowers 1, J.A. Blomfield 2, L.A. Waldron 3, L.H.A. Morris 2, I.D. Pryor 1

1 Fiber Fresh Feeds Limited, 3088 State Highway 5, R D 2, Reporoa, New Zealand2 Equibreed NZ Ltd, 399 Parklands Rd, R D 1, Te Awamutu, New Zealand3 LWT Animal Nutrition Ltd, P O Box 119, Feilding, 4740, New Zealand

Stallions have poor semen quality compared to pro-duction animal species which are selected for fertility.Furthermore, many stallions are exposed to high work-loads, which produce reactive oxygen species that candestroy sperm plasma membranes and reduce fertility[Hartlova et al., 2013 Acta Vet. Brno, 82, 031-035].The in-clusion of a high quality forage in the diet with a low gly-cemic index, highly digestible protein and complex aminoacids, is important for health and may have beneficial ef-fects on semen quality. This preliminary study used asemen freeze-thaw model to compare the effects of addingthe HNF Fiber� based Trial Product (FiberProtect�) to thediet when compared to control stallions randomly selectedfrom a pool of proven breeding stallions. Twelve mixedbreed stallions (age range 4 -18yo, body weight range 350 –

550kg) of proven fertility were used in the trial. The stal-lions were randomly allocated to one of two groups, i) HNFFiber� treatment (n¼6): fed a diet containing approxi-mately 2 kg per 200 kg BW per day of FiberProtect� (whichreplaced the chaff component of their original diet),pasture and a commercial balanced ration and ii) Untreatedcontrol (n¼6): maintained on their existing diet which wascomprised of lucerne chaff, pasture and a commercialbalanced ration. The HNF Fiber� treatment group receivedthe diet for a total of 56 days prior to commencement of thesemen collection period. Once stallions in both groups wereon a regular ejaculation schedule, three ejaculates werecollected from each stallion. The sperm was frozen at 300x106/ml in 0.5ml straws in lactose-EDTA-glycerol diluent in

Table 1

Sperm parameter Control group (mean % � SEM)

Tail defects – raw 17.0 � 3.0Tail defects – post thaw 13.1 � 1.9Midpiece defects – post thaw 9.6 � 1.2

liquid Nitrogen vapor. Samples were evaluated for spermmotility and morphology at the following times i) raw ii)immediately post thaw t¼ 0min iii) post thaw t¼ 10min, togive an assessment over time so that longevity could beinvestigated. Sperm motility was assessed by a blindedassessor at 400x magnification on a heated stage andspermmorphology was assessed by eosin-nigrosin stainingusing phase contrast under oil at 1000x magnification. Alldatawere analysed in UNISTAT� Statistical package version5. Data were analysed by ANOVA for the effect of treatmentand Pair-wise comparisons of means were made using thepost hoc Tukey-HSD test. There were no significant differ-ences between the treatment and control groups for totalmotility or velocity at any time point, however there was asignificant difference between the control and HNF Fiber�treatment group in the total progressive motility of the rawsperm and post thaw at t ¼ 0min or t ¼ 10min (P<0.05).There were no significant differences in the percentages ofhead or midpiece defects before freezing for both the HNFFiber� treatment group and the control group; however,post thaw, the HNF Fiber� treatment group had signifi-cantly less midpiece defects than the control group (Table1). A significant beneficial effect of HNF Fiber� treatmentwas observed on the percentage of tail defects whencompared to the untreated control group raw and postthaw (Table 1). These results suggest a beneficial effect ofHNF Fiber� treatment on sperm tail and midpiecemorphology that could have positive implications for stal-lion fertility that warrants further investigation.

Treatment group (mean % � SEM) P value

10.2 � 1.5 0.04726.6 � 0.8 0.00415.8 � 0.9 0.0131