Livestock Science 225 (2019) 47–52
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Lepidium cake as a feedstuff for pigs a
Hagos Arefaine , Lotta Rydhmer , Roger Andersson , Emma Ivarsson a b c
Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala, Sweden Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden Department of Molecular Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
Keywords: Pigs Lepidium cake Glucosinolate Fiber
The European reliance on imported protein feed for animal feed is not considered sustainable. A way to improve the sustainability of pig production could be by increasing the use of locally produced feedstuff and co-products that are not used for human consumption. Thus, there is a need to explore novel feed resources. Field cress, Lepidium campestre, is a wild Brassica species and is very winter hardy, thus, it can grow even in the northern part of Europe. Currently there is an interest in developing L. campestre for future food (oil) and biodiesel production. Besides, its cake has previously been suggested as a feed source to animals. Therefore, a total of 8 pigs having an initial body weight of 26.5 kg (standard deviation: ± 2.5 kg) were used in a 44-d feeding experiment to evaluate the effect of different inclusion rates of lepidium cake (LC) on palatability, coefficient of total tract apparent digestibility (CTTAD), blood profile, and feeding behavior. A total of 4 diets were formulated: a cereal-based control diet and 3 diets containing 4, 8, and 12% of LC (LC4, LC8, and LC12). The experiment was conducted in change-over design, using 4 diets and 4 periods. Each period consists of 11 d, including 7 d of adaptation followed by 4 d of faeces collection. Fecal samples for CTTAD determinations were collected at d 8, 9, 10, and 11 of each period. Blood samples were collected and analyzed at d 8 of each period. Feeding behavior was evaluated in d 1 and 8 of each period. The result of the study showed that the CTTAD of dry matter, organic matter, crude protein, dietary fiber, non-starch polysaccharides, and gross energy was linearly and quadratically affected by diet (P < 0.001). On the other hand, the CTTAD of ether extract was not affected linearly or quadratically. Eating time was not affected by different inclusion rates of LC, but longer eating time (P < 0.05) was recorded in pigs fed the control diet than those fed different inclusion rates of LC. Eating rate was (P = 0.01) also affected by treatment. Accordingly, greater eating rate was documented in pigs fed diet containing 12% LC than those fed the control diet. Furthermore, pigs eating control feed showed a greater frequency of feeding behaviors (searching, throwing, rooting, and moving feed) than those consuming the diet containing 4% of LC. We can suggest that LC is palatable feed to grower pigs, but the result would indicate that the presence of high total dietary fiber and glucosinolate in the cake reduced its CTTAD and energy value.
1. Introduction The European reliance on imported protein feed for animal feed is not considered sustainable (Tallentire et al., 2018). A way to improve the sustainability of animal production could therefore be to increase the use of locally produced feedstuff and co-products that are not used for human consumption. Thus, there is a need to explore novel feed resources to be able to minimise the environmental impact of animal production. In Northern Europe the main oilseed crop is winter rapeseed and rapeseed cake is a valuable protein-rich ingredient in pig feed. Rapeseed has, however, a weak winter hardiness and cannot be grown further north than the south of Sweden. With a new, winter-hardy ⁎
oilseed crop it would be possible to increase the production of plant oil in cold climate regions (Ivarson, 2016). Field cress, Lepidium campestre (L. campestre), is a wild Brassica species. It is very winter hardy and has a high yield potential (5 t per hectare; 30% greater yield than winter rapeseed) with an upright stature and synchronous flowering, i.e., a good domestication candidate (Ivarson et al., 2013). The plant is biennial and thus also a potential catch crop, which can be grown in space between 2 main crops that could reduce nutrient leakage from the fields (Ivarson, 2016). L. campestre is therefore domesticated in a research program called Mistra Biotech. Currently, there is an interest in developing L. campestre for future food (oil) and biodiesel production. Besides, its cake has previously been suggested as a protein source to animals (Andersson et al., 1999).
Corresponding author. E-mail address: [email protected]
https://doi.org/10.1016/j.livsci.2019.04.022 Received 3 February 2018; Received in revised form 8 April 2019; Accepted 30 April 2019 Available online 03 May 2019 1871-1413/ © 2019 Elsevier B.V. All rights reserved.
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Nutritionally, L. campestre is superior to soybean in all indispensable amino acids (Callaway, 2004), but it has a quite high dietary fiber content (440 g/kg) (Andersson et al., 1999). Dietary fiber could be beneficial from an animal welfare point of view as it can increase the satiety and reduce stereotypic behavior in animals fed a restricted amount of feed such as non lactating sows (Brooks, 2005). However, it could negatively affect the digestibility and growth performance of grower pigs. High proportion of cell wall lowers feed intake because of its negative correlation with digestibility (McDonald et al., 2002). As most plant based protein feedstuff, L. Campastre contains anti-nutritional factors where the major concern is the high content of glucosinolates (123 to 138 µmol/g) which is comparable with the amount of glucosinolates reported in old varieties of rapeseed (150 µmol/g) (Andersson et al., 1999). The recommended maximum inclusion rate of glucosinolate in the diet of grower pigs is 2.4 µmol/g, (RothMaier et al., 2004), which indicate that the maximum inclusion rate of the new varieties of rapeseed is about 13%. When pigs have been fed rapeseed diets with higher glucosinolate rate then the recommended, negative effects on digestibility, health, feed intake and feed choice have been observed (Choi et al., 2015; Kyriazakis and Emmans, 1991). To reach the maximum recommended glucosinolate inclusion rate with L. campastre, only 1.6% inclusion rate in the diet is needed. However, the types of glucosinolates present in rapeseed and L. campestre are completely different (Andersson et al., 1999). The main glucosinolates constituent in old variety rapeseed are progoitrin, gluconapin, glucobrassicana-pin, napoleiferin, glucoraphanin, glucoalyssin, glu-cobrassicin, and neoglucobrassicin (Bell, 1984; Choi et al., 2015) and for double 00- rapeseed is 4-hydroxyglucobrassicin (Sørensen and Sørensen, 2004). Whereas, sinalbin is the main glucosinlate in L. campestre. As a result L. campestre might have less tendency of toxicity than old rapeseed variety, but a study done in rat showed that the sinalbin negatively affected palatablity and protein utilization (Bille et al., 1983). To our knowledge, the potential of lepidium cake (LC) as livestock feed has not been studied before. Hence, the objective of this study was to explore if LC could be a potential feedstuff for pigs by studying the effect of inclusion rate of LC on total tract apparent digestibility, blood profile and feeding behavior in grower pigs.
Table 1 The ingredient composition (as-fed basis) and analyzed composition of the experimental diets (% of DM). Lepidium cake (%) Ingredients Barley Wheat Wheat bran Wheat middling Lepidium cake Soy bean protein concentrate Limestone Lysine NaCl Mineral and vitamin premixa Threonine Methionine TiO2 Analyzed composition of diets DMb OMc CPd Ash EEe DEf (calculated) Total P (calculated) Total Ca (calculated) Indispensible amino acids in g / kg DM Lys Met Thr Cys
0 52.0 25.0 10.0 8.0 0.0 2.0 1.7 0.4 0.4 0.4 0.1 0.1 0.3
4 49.9 24.0 9.6 7.7 4.0 1.9 1.6 0.4 0.3 0.4 0.1 0.0 0.3
8 47.8 23.0 9.2 7.4 8.0 1.8 1.6 0.4 0.3 0.4 0.1 0.0 0.3
12 45.7 22.0 8.8 7.0 12.0 1.8 1.5 0.4 0.3 0.4 0.1 0.0 0.3
91.0 85.3 12.0 5.7 2.6 13.1 0.47 0.83
91.6 84.8 12.3 5.8 3.0 12.3 na na
91.2 85.4 12.8 5.8 3.3 12.3 na na
91.6 85.6 13.0 6.0 3.7 12.4 na na
8.7 2.7 5.3 2.7
na na na na
na na na na
na na na na
a The mineral and vitamin premix provided the following per kilogram of diet: Minerals (g): Ca: 0.79; P: 0.001; Mg: 0.07; K: 0.002; Na: 0.003; Cl: 0.001; S: 0.18. Trace minerals (mg): Fe, 108; Cu, 40; Mn, 54; Zn, 200; Co, 0.0006; I, 0.532; Se: 1.07; Cr, 0.002 Vitamins: Vitamin A: 13333 IU; vitamin D3, 1333 IU; vitamin E, 1600 mg; vitamin K3, 5.3 mg; vitamin B1, 5.3 mg; vitamin B2, 10.7 mg; vitamin B3, 533 mg; vitamin B5, 32 mg; vitamin B6, 8.0 mg; vitamin B12, 0.05 mg. Phytase: 500 FTU (Danisco Animal Nutrition, Marlborough, Wiltshire, UK). b DM, dry matter. c OM, organic matter. d CP, crud protein. e EE, ether extract. f DE, digestible energy (MJ/kg DM) and na, not analyzed. 0, 4, 8, and 12 represents pigs fed cereal based control diet supplemented with lepidium cake at the inclusion rates of 0, 4, 8, and 12%, respectively.
2. Material and methods 2.1. Pigs and housing The experiment was conducted using 8 female growing pigs (Landrace × Yorkshire × Hampshire) with an initial body weight of 26.5 kg (standard deviation: ± 2.5 kg). The pigs were housed in individual pens that allowed nose contact with the neighbour pig. The pens had concrete floor equipped with a rubber mat; the pigs had no access to straw during the experiment. Each pen was supplied with plastic toys as occupation for the pigs. All pigs had ad libitum access to water through nipple drinker during the entire experiment. The daily feed allowance was 4% of body weight and the pigs were fed twice daily (07:00 and 15.00 h) in equal portions. To adjust the daily allowance, pigs were weighed at d 0, 11, 22, 33, and 44. At the end of the experiment, the average body weight of pigs was 52.5 kg (standard deviation: ± 4.5 kg). The experiment was carried out at the pig facilities in the Centre for Veterinary Medicine and Animal Science of the Swedish University of Agricultural Sciences (Uppsala, Sweden) and was approved by the ethical committee of the of Uppsala region.
period 1. Each period lasted a total of 11 d including 7 d adaptation followed by 4 d sample collection. 4 diets were formulated by replacing 0, 4, 8, and 12% of a cereal based control diet with LC (Table 1). The LC was a residue after mechanical extraction of the oil from the lepidium seed. The control diet was composed of barley, wheat, soya bean protein, amino acids, premix, and indigestible marker of titanium dioxide (Ti02) (Table 1). The control diet was formulated based on the Swedish nutrient requirement of grower pigs (SLU, 2018; Tables 2 and 3). All ingredients were milled through a 3.5 mm screen before they were mixed and pelleted (3 mm). All diets were supplemented with 2.5 g of Ti02/kg for digestibility calculations.
2.2. Experimental design and treatments
2.3. Fecal and blood sample collection
During the adaptation period of one week (before the start of the actual experiment); the pigs were fed with cereal based control diet. The experiment was performed with a change-over design in a double 4 × 4 latin square, using 8 grower pigs, 4 treatments, and 4 periods. The feeding order for the pigs was randomly allocated before start of
Fresh faecal samples of each pig were collected daily from d 8 to 11 of each period. The samples of each pig and each period were pooled and stored at −20 °C until chemical analyse. A blood sample from each pig was collected from the jugular vein at the end of each period. The blood samples were analyzed immediately after collection using an I48
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control diet and diets containing different inclusion rates of LC was calculated using Ti02 as indigestible marker (Fastinger and Mahan, 2006) according to the equation:
Table 2 Analyzed chemical composition of dietary fiber in g per kg DM of lepidium cake and the experimental diets. Lepidium cake (%) Type of nutrient OM CP Ash EE NSPa Total Insoluble Arabinose Total Insoluble Xylose Total Insoluble Mannose Total Insoluble Galactose Total Insoluble Glucose Total Insouble Uronic Acid Total Insoluble Klason lignin Total dietary fiber a
CTTADT = 1
0 853 120 57 26
4 848 123 58 30
8 854 128 58 32.5
12 856 130 60 37
where CTTADT is coefficient of apparent digestibility of the nutrient in the test diet, TiF is Ti02 concentration in the feed in g/kg, Nf is nutrient concentration in faeces in g/kg, NF is nutrient concentration in the feed (g/kg), and Tif is Ti02 concentration in faeces in g/kg.
2.5. Feeding behavior
203 191 123 519
9 7 14 181
15 13 18 191
23 20 21 196
30 28 24 213
The feeding behavior of the pigs was studied at first and eighth d of each period. Eating time (in min) was analyzed from the time the feed was offered to the pig until all feed in the trough was finished. Eating rate (in g/min) was calculated as amount of feed consumed per eating time. The frequency of the feeding behaviors rooting, searching, throwing, and moving feed were recorded during the morning feeding from 7:30 to 9:30 h. In the analysis, the frequencies of all these feeding behaviors were summed to a variable called “ FeedBeh ”. A feed choice test was carried out in the first and last day of the experiment using control diet and diet containing 12% of LC. In the test, 60 g of the control diet was placed in one corner of the through and 60 g of the diet containing 12% of LC was placed in the other corner. The test was repeated in a second round after 5 min. The position of the 2 diets was changed between pigs and rounds. The first feed chosen by the pig was recorded in each round, and the frequency of visits to each diet was continuously recorded for 5 min per round. Besides, at the end of the second round, feed left in the feed trough was recorded.
NSP, non starch polysaccharides.
2.6. Statistical analysis
Table 3 Effect of experimental diets on growth performance of pigs. Lepidium cake (%) Item ADFIb, g ADGc, g G:Fd
0 1358 644 0.46
((TiF x Nf)/(TifxNF))
LC 850 183 78 132
4 1384 595 0.42
The data on growth performance, CTTAD, blood profile, and feeding behavior were analyzed using Proc Mixed procedure SAS (Version 9.4; SAS Inst. Inc., Cary, NC, US). The model for growth performance, CTTAD, blood profile, feeding behavior (eating time, eating rate, and FeedBeh), treatments (control, 4, 8, and 12% LC), and periods (I, II, III, and IV) as fixed factor, while the individual pig as random factor. The effect of week and dietary treatment on CTTAD, blood profile, and feeding behavior is presented using least square means. The orthogonal polynomial contrast test was performed to determine linear and quadratic effects of increasing inclusion rates of LC. P-values > 0.05 were considered as non-significant.
Contrasts 8 1362 594 0.43
12 1392 592 0.42
SEMa 48 30 0.01
Linear 0.940 0.160 0.189
Quadratic 0.048 0.262 0.064
a SEM, standard error of mean; bADFI, average daily feed intake; cADG, average daily gain and dG:F, gain to feed ratio.
STAT analyser. Blood samples was injected into EC8+ cassettes inserted into an I-STAT portable analyser (I-STAT Corporation, East Windsor, NJ, US) that measured the blood pH, haematocrit, blood glucose, haemoglobin (Hb), urea nitrogen, blood carbonate (HCO3−), total carbon dioxide (TCO2), anion gap (AnGap), and base excess (BE), Na+, K+, and Ca+).
3. Results 3.1. Growth performance, CTTAD and digestible energy (DE) There was a quadratic trend of lepidium cake inclusion rates on the average daily feed intake (Table 4). Lepidium cake inclusion reduced
2.4. Chemical analysis Samples of feeds and faeces were analyzed for dry matter (DM) by drying in oven at 103 °C overnight and for ash by burning the samples in muffle furnace at 550 °C for 3 h (AOAC, 2000). Nitrogen (N) in the samples was first analyzed by Kjeldahl method (Nordic committee on food analysis, 2003) then crude protein (CP)% was calculated through multiplying% of N by factor 6.25. Ether extract (EE) was determined according to the EC (1998). The gross energy (GE) of feed and fecal samples was determined through Bomb calorimetry (Parr Instruments 1563, Moline, IL, US). Non-starch polysaccharides (NSP) constitutes, lignin and total dietary fiber (TDF) were analyzed according to the Uppsala method (Theander et al., 1995). Ti02 in the feed and faeces were determined according to Short et al. (1996).
Table 4 Coefficient of total tract apparent digestibility of DM, OM, CP, GE, DF and NSP. Lepidium cake (%) Item DM OM CP GEa EE DFb NSP Arabinose Xylose Uronic Acid
2.4.1. Calculation The Coefficient of total tract apparent digestibility (CTTAD) of
0 0.81 0.83 0.81 0.80 0.62 0.45 0.52 0.54 0.56 0.40
4 0.75 0.77 0.73 0.75 0.60 0.31 0.42 0.46 0.47 0.19
8 0.74 0.77 0.74 0.75 0.66 0.30 0.40 0.47 0.49 0.15
Contrasts 12 0.73 0.76 0.73 0.74 0.73 0.29 0.41 0.49 0.51 0.16
GE, gross energy and bDF, dietary fiber.
SEM 0.01 0.01 0.01 0.01 0.01 0.02 0.01 0.01 0.01 0.03
Linear <0.001 <0.001 <0.001 <0.001 0.820 <0.001 <0.001 <0.001 <0.001 <0.001
Quadratic <0.001 <0.001 <0.001 <0.001 0.227 <0.001 <0.001 0.006 <0.001 0.004
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Table 5 Least square means, standard deviation of mean (SD), min, and max values of eating time and eating rate per week. Eating time (min) Week 1 2 3 4 5 6 7 8 ab
Mean 103a 26b 21b 32b 17b 15b 12b 23b
SD 38 1 1 1 1 4 1 2
Table 7 Least square means, mode, min, and max frequency of feeding behavior (FeedBeh) of different treatments.
Eating rate (g/min) Min 37 19 17 27 17 8 17 26
Max 121 23 19 31 20 21 19 32
Mean 7b 25a 33a 21a 39a 50a 49a 31a
SD. 4 3 4 2 5 21 6 4
Min 4 21 29 18 33 33 40 27
Max 14 30 38 24 47 100 48 36
the CTTAD of all measured parameters except EE in a linear and quadratic trend (Table 5). The DE in the control diet was 13.05 MJ/kg DM. While the DE content of diets containing 4, 8, and 12% of LC was 12.33, 12.35, and 12.32 MJ/kg DM, respectively. 3.2. Blood profile and feeding behavior The blood electrolytes (Na+, K+, Cl-, AnGap and glucose), haematology (Hct and Hb), and blood gasses (pH, pCO2, TCO2, HO3−1, and BE) were not affected by the control diet as well as diets containing different inclusion rates of LC. In the first period; the pigs were offered 683–715 g of feed daily, depending on body weight. A total of 3 pigs (one control, one LC4, and one LC8) did not finish eating within 120 min in the first day of the experiment. They were included in the analysis with a value of 121 min. The following weeks all pigs ate all feed within 120 min. In the last period, the pigs were offered 752–1040 g of feed daily. The average eating time and eating rate are presented in Table 6. Eating time was affected by week (P < 0.01). Accordingly, longer eating time was documented in wk 1 than in all other weeks. Eating rate was highly affected (P < 0.01) by feeding weeks. Pigs showed lower eating rate (7 g/min) in week 1 than in later weeks (Table 6), but no clear time pattern was observed. Longer eating time (P < 0.05) was recorded in pigs fed the control diet than those fed different inclusion rates of LC. Eating time was not affected by different inclusion rates of LC (Table 6). Eating rate tended (P = 0.01) to be affected by treatment. The pigs showed a tendency to consume diet containing the 12% LC faster than those fed the control diet; however no significant difference was found between the other treatments (Table 7). The pigs showed more FeedBeh (P < 0.05) in wk 2 as compared with wk 8, but no significant difference was found between the other weeks. The pigs tended to show more FeedBeh activities when they consumed the control diet than those fed diet containing 4% of LC, but no significant variation was recorded among the other treatments (Table 7). FeedBeh d 1 and d 8 of the same treatment was compared within pig. 4 pigs eating control showed more FeedBeh on d 1 than d 8.
Mean 35a 29b 33b 28b
SD 33 25 33 25
Min 15 17 17 8
Mean 28b 31ab 31ab 36a
SD 13 14 13 23
Min 4 5 4 5
0 4 8 12
2.1a 1.1b 1.4ab 1.6a
0.0 0.0 0.0 1.0
0.0 0.0 0.0 0.0
6.0 3.0 5.0 6.0
Different letters in a column, indicate difference (P < 0.05).
To our knowledge, there is no previous study conducted on feeding value of LC to pigs and other animals. The results from the current study showed that the CTTAD of DM, OM, CP, GE, DE, DF, and NSP were reduced in pigs fed diets containing LC than those fed the control diet. Lepidium cake has a high content of DF (519 g/kg) of which 95% are insoluble dietary fiber consisting mainly of uronic acid, Klason lignin, and glucose. The major component in the control diet was barley, a cereal with about 25% soluble dietary fiber (Bach Knudsen, 1997) and substantially lower amount of Klason lignin compared to LC. Increased inclusion rate of LC at the expense of the control diet therefore increased the amount of insoluble dietary fiber which likely is the main reason for the lower CTTAD values. Similarly, negative correlation between dietary NSP and apparent digestibility were reported by Sklan et al. (2004) and Wilfart et al. (2007). The increased microbial fermentation in the hindgut with increasing DF content in the diet diets also increases the endogenous loss of nitrogen and amino acids (Bindelle et al., 2009; Jha and Berrocoso, 2015). To correct for the endogenous protein losses, ileal digestibility, and calculation of standardized or true ileal digestibility is commonly used (Stein et al., 2007). However, in the current study, it was not possible to get ileal digesta samples, hence, it is likely that the protein digestibility in this study is under estimated. The fat content in diet containing 4, 8, and 12% of LC were 3.00, 3.25, and 3.70%, respectively. According to Andersson et al. (1999), L. campestre seed contains about 20% of crude fat which is greater than the fat content in the current study. However, in the current study some oil was mechanically removed and the remaining part, the press cake was used. The CTTAD of EE was the only digestibility parameter that was not reduced linearly or quadratically with LC inclusion rate. Brooke (2010) reported increased CTTAD of EE as the inclusion rate of oil seed cakes in the diet increased, which was explained with increasing supply of poly unsaturated fatty acids (PUFA). Andersson et al. (1999) reported that linolenic acid was the main fatty acid in L. campastre, and increasing PUFA in the diets with increasing the inclusion rate of LC may explain the contrasting effect on CTTAD of EE compared to the other digestibility parameters. The presence of glucosinolates might be another reason for the lower CTTAD of DM, OM, CP, GE, DF, and NSP in diet containing different inclusion rates of LC. According to Roth-Maier et al. (2004) the maximum inclusion rate of glucosinolate in grower pig fed rape seed is
Eating rate (g/min) Max 121 121 121 115
Table 6 Least square means, deviation of mean (SD), min, and max values of eating time and eating rate per treatment.
Lepidium cake (%) 0 4 8 12
The corresponding results for diet containing 4, 8, and 12% of LC were 2, 4, and 3 pigs. In the feed choice test the pigs ate small amounts of each feed and shifted repeatedly between the feeds, without showing preference for any of the feeds. In average the pigs moved between the feeds 16 times during 5 min. At the first day pigs choose to start with the control feed in 5 of the 16 records. At the last day pigs choose to start with the control feed in 11 of the 16 records. During the second round of the first day 1 pig ate all feed, 2 pigs left equal amounts of control and diet containing 12% of LC, 2 pigs left only control feed and 3 pigs left only diet containing 12% LC. After the second round of the last day no pigs had any feed left.
Different letters in a column, indicate difference (P < 0.01).
Eating time (min)
Lepidium cake (%)
Max 47 52 52 100
Different letters within eating time, in a column, indicate difference (P < 0.05). ab Different letters within eating rate, in a column, indicate difference (P = 0.01). 50
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2.4 μmol/g of diet. In the current study, the total glucosinolate content in diets containing LC was not analyzed. The amount of glucosinolates in mechanically extracted cake is about 1.8 times greater than the whole oil seed (Beltranena and Zijlstra, 2012). Accordingly, the glucosinolate content in the current study was 248, 10, 20, and 30 μmol/g in diet containing 4, 8, and 12% LC, respectively, which is beyond the glucosinolate tolerance rate of grower pigs. In the interdisciplinary research program Mistra Biotech at SLU, L. campestre is genetically changed to improve the oil quantity and quality, but no effort to decrease the glucosinolate content of the plant has been made yet. Therefore, developing L. campestre variety with a lower glucosinolate content that meets the EU standard is necessary to fully utilize LC as an animal feed. Bille et al. (1983) pointed out that the glucosinolate sinalbin interferes with the activity of digestive enzyme and absorption of nutrient. The anti-nutritional and toxic effects of sinalbin have previously been studied in a rat model with increasing inclusion rate of sinalbin from 1 to 5 mg/g DM (Bille et al., 1983). The authors concluded that inclusion rate of sinalbin at more than 1 mg/DM affects the protein utilization and goitrogenic effect. We do not know much about pigs’ glucosinolate sinalbin tolerance inclusion rate, which was why we did the feed behavior and blood parameters measurements. We tried to analyses blood urea to investigate whether the sinalbin interferes with protein utilization. But the urea nitrogen in all treatment was below 1 and was excluded from further analysis. The low values in the current study might be because of the analyses method was not sensitive enough. Hence, another method of analysis or a study at wider inclusion rate (0, 10, 20, and 30% of LC) is needed to confirm whether LC affects protein digestibility and utilization. None of the blood parameters were affected by the different inclusion rates of LC. This indicates that LC did not induce any major effect on alkaline tides and or diet buffering capacity (Huyben et al., 2017), or induced anaemia in the pigs. Palatability of diet can be either positively or negatively influenced by a post—ingestive effect through a response sent from hypothalamus to change, stop or continue eating on the same diet (Gonyou et al., 2012). In the current study, feed intake was not linearly affected by LC inclusion rate. This implies that the control and the diets with increasing inclusion rate of LC were equally palatable to grower pigs. Pigs showed a low feed intake in the first day of the feeding experiment. This is in agreement with Gonyou et al. (2012) who reported a low feed intake in the first day of the study when grower pigs were fed pea based diet. However, our pigs fed control diet also had a low feed intake the first day. If the inclusion rates of LC had resulted in a negative post ingestive effect then a low feed intake would have been seen also at d 8. Neophobia is a means by which animals avoid consuming new diets to avoid eating toxic ingredients (Rozin and Vollmecke, 1986). An animal's innate response when offered new diet is neophobia followed by exploratory behavior (Misslin and Cigrang, 1986). Only 2–4 of our 8 pigs showed more FeedBeh the first day they ate a diet than the last d. In general pigs fed control diet showed more FeedBeh than those fed diet containing 4, 8, and 12% of LC. This could maybe be related to the greater fiber content in the diets containing LC, since high fiber content reduces the stereotypic behavior of pigs (Brooks, 2005). It is not likely that the low feed intake on the first day was because of neophobia caused by LC, since low feed intake was also documented in pigs fed control diet. The anti-nutritive factor (glucosinolate) concentration of LC did not seem to affect the palatability of the feed in this study. Eating rate (g/min) was greater in pigs fed the diet containing 12% of LC than those fed control, 4%, and 8% LC (Table 6). The average eating rate was comparable with the values (31–42 g/min) reported in lactating sows (Quiniou et al., 2000). Shorter eating time was reported in grower pigs fed on standard diet than those fed on fibrous diet (Kallabis and Kaufmann, 2012). In the current study pigs fed on the standard diet having low fiber content (181 g/kg DM) showed longer eating time compared with LC feed, which contains higher fiber content (519 g/kg DM). Hence, the reason for why pigs showed shorter eating time and higher eating rate in the LC diets could be that the pigs liked
the taste of the LC diets more than the taste of the cereal based control diet. According to the feed choice test, feed choice was not affected by the feed type; pigs choose to start with the 12% LC feed as often as the control feed. 5. Conclusions Lepidium cake is a palatable feed for grower pigs. It does not seem to cause any detrimental health effect, however its high inclusion rate of insoluble NSP and glucosinolates content result in low apparent digestibility. Sows or ruminant animals would therefore likely digest LC to a greater extent than grower pigs. Conflict of interest statement All authors declare no conflict of interest. Acknowledgement The study was financed by Mistra, the Swedish Foundation for Strategic Environmental Research, together with the Swedish University of Agricultural Sciences in the research program Mistra Biotech. Reference Andersson, A.A., Merker, A., Nilsson, P., Sørensen, H., Åman, P., 1999. Chemical, composition of the potential new oilseed crops barbarea vulgaris, barbarea verna and, lepidium campestre. J. Sci. Food Agric. 79, 179–186. AOAC, 2000. Official Methods of Analysis, 17th ed. Association of Official Analytical Chemists, Washington, DC, US. Bach Knudsen, K.E., 1997. Carbohydrate and lignin contents of plant materials used in animal feeding. Anim. Feed Sci. Technol. 67, 319–338. Bell, J.M., 1984. Nutrients and toxicants in rapeseed meal: a review. J. Anim. Sci. 58, 996–1010. Beltranena, E., Zijlstra, R.T., 2012. Oilseed co-products as alternative ingredients. Adv. Pork Prod. 23, 55–65. Bindelle, J., Buldgen, A., Delacollette, M., Wavreille, J., Agneessens, R., Destain, J.P., Leterme, P., 2009. Influence of source and concentrations of dietary fiber on in vivo nitrogen excretion pathways in pigs as reflected by in vitro fermentation and nitrogen incorporation by fecal bacteria. J. Anim. Sci. 87, 583–593. Bille, N., Eggum, B.O., Jacobsen, I., Olsen, O., Sørensen, H., 1983. Antinutritional and toxic effects in rats of individual glucosinolates ( ± myrosinases) added to a standard diet. Z. Tierphysiol. Tierernahr. Futtermittelkd. 49, 195–210. Brooke, G., 2010. The effects of dietary fat supplementation on grower or finisher pig performance and digestibility. https://trove.nla.gov.au/work/39166858 (accessed 10. 09.18). Brooks, P.H., 2005. Effect of diet on the behavior and welfare of pigs. https://www. reseachate.net/pulication/254845627 (accessed 10.09.18). Callaway, J.C., 2004. Hempseed as a nutritional resource: an overview. https://link. springer.com/article/10.1007/s10681-004-4811-6 (accessed 10.09.18). Choi, H.B., Jeong, J.H., Kim, D.H., Lee, Y., Kwon, H., Kim, Y.Y., 2015. Influence of rapeseed meal on growth performance, blood profiles, nutrient digestibility and economic benefit of growing finishing pigs. Asian-australas. J. Anim. Sci. 28, 1345. EC, 1998. Commission Directive 98/64/EC of 3 September 1998 establishing community methods of analysis for the determination of amino acids, crude oils and fats, and olaquindox in feeding stuffs and amending directive 71/393/EEC. Off. J. Eur. Comm L 257/23. Fastinger, N.D., Mahan, D.C., 2006. Determination of the ileal amino acid and energy digestibilities of corn distillers dried grains with soluble using grower-finisher pigs. J. Anim. Sci. 84, 1722–1728. Gonyou, H.W., Beaulieu, D.A., Mutsvangwa, T., Stookey, J.M., Whiting, S.J., 2012. Behavioral Analysis of Pigs When Presented With Pea Diets. University of Saskatchewan, Saskatchewan, Canada MS Thesis. Huyben, D., Vidakovic, A., Nyman, A., Langeland, M., Lundh, T., 2017. Effects of dietary yeast inclusion and acute stress on post-prandial whole blood profiles of dorsal aortacannulated rainbow trout. Fish Physiol. Biochem. 43, 421–434. Ivarson, E., Ahlman, A., Li, X.Y., Zhu, L.H., 2013. Development of an efficient regeneration and transformation method for the new potential oilseed crop Lepidium campestre. BMC Plant Biol 13 (15). Ivarson, E., 2016. Development of Lepidium Campestre in to a New Oil and Catch Crop. Swedish University of Agricultural Sciences, Uppsala, Sweden PhD Diss. Jha, R., Berrocoso, J.D., 2015. Review: dietary fiber utilization and its effects on physiological functions and gut health of swine. Animal 9, 1441–1452. Kallabis, K.E., Kaufmann, O., 2012. Effect of a high-fiber diet on the feeding behavior of fattening pigs. Archiv Tierzucht 55, 272–284. Kyriazakis, I., Emmans, G.C., 1991. Diet selection in pigs: dietary choices made by growing pigs following a period of underfeeding with protein. Anim. Prod 52,
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