The present study sought to find out how carotenoid supplement influences on body weights, feed consumption and reproductive success in standard farm mink (<i>Neovison vison</i>). Carotenoids were from microalgae <i>Haematococcus pluvialis</i>. A dose of carotenoid supplement of 0.20, 0.25, 0.20, 0.20, and 0.10 g/animal was added daily in feed in February, March, April, May and June, respectively. Experimental groups were: 1) control group, and 2) carotenoid group. Each group comprised 100 females and 25 males. The results showed that appetite of animals in all groups was good. Significant differences were not found in body weights before breeding. However, weights of control females were significantly (P < 0.05) lower compared with those of carotenoid fed animals when kits aged 21 days. At the age of 21 and 42 days, body weights of kits were similar in both groups. However, kits from carotenoid group tended to grow better (P < 0.1) than those from control group. Number of whelped females was lower in control group (81 vs 85 females). Number of barren females was higher in control than in carotenoid group (16 vs 13 females). Significant differences were not found in number of kits per mated and whelped female. Number of lost kits was higher in the control group at the age of 21 days (24 vs 20 kits) and the age of 42 days (40 vs 26 kits). The present study showed that carotenoid supplement could be used in mink diet. The results are promising, but require further studies before final implementation.
Carotenoids are molecules that typically consist of carbon, hydrogen and in some cases oxygen. They can be found commonly in nature. Mammals cannot form their own carotenoids and are dependent on the carotenoids received from food. Mammals typically have a good ability to metabolize ingested carotenoids, and even reform species-specific carotenoids [
Carotenoids are known to have both antioxidative and immunological effects [
The mink (Neovison vison) is a small-sized mustelid species (Family Mustelidae) housed commercially for its excellent fur [
The aim of the present study was to find out how carotenoid supplement in traditional farm feed affects mating and whelping performance and kit mortality of farm-raised mink. Effects on body weights were also evaluated in adults and kits of both sexes.
The present study was carried out at the Fur Farming Research Station of MTT, in Kannus, western Finland (63.54˚N, 23.54˚E). The use of experimental animals was evaluated and approved by the Animal Care Committee of MTT Agrifood Research Finland. Health of animals was visually checked daily. Health evaluation was based on general appearance of animals, including consistence of faeces. Solid faeces were considered normal, loose faeces indicated diarrhea.
Experimental animals employed were dark colored standard mink born at the research station. Two experimental groups were formed: 1) control group; and 2) carotenoid group. Each group comprised 100 females and 25 males. Only healthy animals free from plasmacytosis were used. Animals were first mating season juveniles. They were kept in traditional two-row sheds. Animals were singly housed in wire-mesh cages measuring 70 cm long × 30 cm wide × 38 cm high. Males were placed in every fourth cage between the females. After mating, males and unmated females were removed from the experimental shed.
Fresh feed was manufactured at the feed kitchen of the MTT research station. Same ingredients were used throughout the study. Ingredients were grinded by using Stephan Universal machine grinder, type UM 44. Feed analyses were made three times during the study. Samples for analyses were collected for the following periods: February 9 - 14, April 3 - 11, and May 28 - 31, respectively. Animals were fed once a day by hand. The amount of given feed and leftovers were measured on a group basis with a Mettler SM 15 balance, accuracy ±1 g.
The base of the feed was the same for both groups (
Vitamins per kg of food were: retinol 1.05 mg; cholecalciferol 0.009 mg; alpha-tocopherol 40 mg; thiamine 15 mg; riboflavin 6 mg; cyanocobalamine 0.02 mg; pantothenic acid 5 mg; nicotine acid 10 mg; pyridoxine 3
Ingredient (%) | February-March | April-May | June |
---|---|---|---|
Slaughterhouse offal | 11.5 | 12.0 | 12.0 |
Poultry offal | 11.5 | 12.0 | 12.0 |
Baltic herring | 30.0 | 29.0 | 29.0 |
Fishmeal | 6.0 | 7.0 | 8.0 |
Cereals1 | 12.5 | 11.0 | 10.0 |
Vitamins2 | 1.5 | 1.5 | 1.5 |
Soybean oil | - | - | 0.5 |
Water | 26.0 | 27.5 | 26.9 |
1Cooked barley and wheat; 2See material and methods.
Variable | February-March | April-May | June |
---|---|---|---|
Dry matter (DM), % | 34.3 | 34.1 | 34.6 |
In DM%, Ash | 7.8 | 9.5 | 10.0 |
Crude protein | 37.1 | 39.2 | 38.9 |
Crude fat | 19.2 | 20.5 | 23.4 |
Crude carbohydr. | 36.0 | 30.8 | 27.7 |
ME (MJ/kg DM) | 17.2 | 17.4 | 18.0 |
From ME, %: Protein | 34.4 | 36.0 | 34.5 |
Fat | 40.0 | 42.2 | 46.6 |
Carbohydr. | 25.7 | 21.8 | 18.9 |
Month | Control | Carotenoid supplement | ||
---|---|---|---|---|
Given | Eaten | Given | Eaten | |
February | 582.0 | 582.0 | 582.0 | 582.0 |
March | 630.0 | 625.1 | 630.0 | 625.2 |
April | 562.0 | 555.0 | 562.0 | 556.3 |
May | 530.0 | 494.3 | 530.0 | 499.1 |
June | 444.0 | 394.8 | 444.0 | 417.8 |
Total | 2748.0 | 2651.2 | 2748.0 | 2680.4 |
mg; folic acid 0.3 mg; biotin 0.04 mg. Furthermore, 1 kg mixture food contains: calcium 16.0%; phosphorus 11.0%; magnesium 4.0%; cobalt 40 mg; copper 150 mg; iron 6500 mg; manganese 3000 mg; zinc 6000 mg. Fresh water was freely available from automatic water device system.
Initial body weights of breeding females were measured on February 10 with a Mettler SM 15 balance, accuracy ±1 g [
Matings were started on March 9. Each of the breeding females was mated according to the normal mating routines. Before the breeding season, the testicles of breeding males were palpated to check normality. Mink females were mated according to the 1 + 8 system [
At whelping, the date of parturition and the number of live-born and stillborn kits were recorded. The whelping result was calculated at the age of 2 and 42 days. Females and kits were weighed at the age of 21 and 24 days.
Statistical analyses were performed by the General Linear Models (GLM) procedure of the Statistical Analysis System [
Feed consumption was measured on a group basis (
Body weights of breeding animals are shown in
Males in both experimental groups were very willing to mate. Any abnormal mating behavior was not observed. Reproductive result for females is summarized in
Variable | Control | Carotenoid supplement |
---|---|---|
Breeding females, February 10 | 979.2 ± 132.1 | 991.0 ± 138.6 |
Breeding males, February 10 | 2235.2 ± 227.0 | 2326.4 ± 195.0 |
Breeding females, May 3 | 993.0 ± 106.8 | 972.6 ± 102.7 |
Breeding males, May 3 | 2365.6 ± 237.0 | 2399.2 ± 227.6 |
Whelped females at 21 days | 1074.1 ± 120.5 | 1109.8 ± 131.1* |
Whelped females at 42 days | 978.5 ± 120.0 | 985.7 ± 151.3 |
Female kits at 21 days | 109.3 ± 20.2 | 114.2 ± 19.5 |
Male kits at 21 days | 121.9 ± 23.6 | 125.1 ± 24.6 |
Female kits at 42 days | 254.9 ± 55.0 | 265.0 ± 53.7 |
Male kits at 42 days | 280.3 ± 66.8 | 291.2 ± 64.5 |
Variable | Control | Carotenoid supplement |
---|---|---|
Breeding females, N | 100 | 100 |
Mated females, N | 98 | 99 |
Died before whelping, N | 1 | 1 |
Whelped females, N | 81 | 85 |
Barren females, N | 16 | 13 |
Kits lost at 21 days, N | 24 | 20 |
Kits lost at 42 days, N | 40 | 26 |
Kits per mated female, N | 4.5 | 4.4 |
Kits per whelped female, N | 5.5 | 5.3 |
whelped females was lower in the control group. Furthermore, number of barren females was higher in control than in carotenoid group. Significant differences were not found in number of kits per mated or whelped females. Number of kits lost postpartum was higher in the control group.
An intensive effort was made here to clarify possible effects of dietary carotenoid supplement on reproductive outcome and body weights in farm-raised mink of both sexes. Number of females per group was 100. Both groups included 25 males in addition. Such large groups have been seldom employed for breeding experiments in mink [
Mink diets are typically high in fish and fish products resulting in a high dietary level of long chain polyunsaturated fatty acids. This may cause a kind of oxidative stress to mink [
Data from feed consumption measurements revealed that animals in both study groups consumed the offered feed well. While animals’ appetite was good, it tempts us to conclude that the palatabílity of food containing carotenoid supplement was as good as that of a traditional control feed. Rather similar body weights of animals in both study groups also suggest that feed efficiency was good in both diets. This coincides with previous observations in the mink [
One previous study has examined the effects of algae meal, with high astaxanthin content, on ovulation rate and reproductive outcome in female mink [
In other animals, such as cows and horses, carotenoid supplement has been found to increase the frequency of successful insemination. Furthermore, in rabbits extra carotenoids seem to lead to larger offspring [
The percentage of stillborn kits was reduced significantly with algae meal in previous study [
Previous study also compared milk intake between control and algae meal groups [
The present results together with previous findings [
The present study revealed some differences between study groups. Number of barren females was lower in carotenoid group. Furthermore, number of whelped females was higher in carotenoid diet. The kit mortality tended to be lower and kit growth better in animals from carotenoid group. The results are promising but require further clarifications before studied carotenoid supplement can be implemented.
This study was financially supported by MTT Agrifood Research Finland. The staff of MTT research station is kindly acknowledged for their valuable help in carrying out this experiment. Special thanks to Pekka Toikkanen, Terho Lindqvist, Jaakko Huuki and Aimo Joki-Huuki for good co-operation and technical help. Many thanks are also extended to Juhani Sepponen for statistical analyses.