Lipid Sources To Jersey Cows: Productive, Nutritional Effects and Milk Fatty Acid Compounds

The aim was to assess if the replacement of fatty acid salts by oil seeds in diet of dairy cows and their effects about intake and digestibility, milk production and composition, feed e�ciency, metabolic pro�le and milk fatty acid pro�le. Lipid sources evaluated were calcium salts of fatty acids (CS), linseed (LI), sun�ower (SF) and soybean (SY). Diets were iso in protein, �ber and energy, with 58 g/kg (mean) of crude fat in dry matter. There were no differences (P > 0.05) in the intake of nutrient fractions. The protein digestibility was lower for SY (P < 0.001) due the fraction derived from the grain in that treatment. The ether extract digestibility was higher for CS treatment (P < 0.001), and no difference was found between the grains sources. Milk production was higher in CS, when milk production was corrected for energy, these differences disappeared. Little effect on milk composition (g/kg) was observed, only for lactose. The sources used do not affect feed e�ciency, energy balance and blood metabolic pro�le. in CS. When observed milk fatty acid pro�le, there was an increase in�uence by CS There was no difference for saturated and polyunsaturated fatty acids (PUFA), however, monounsaturated fatty acids (MUFA) were higher for SF (P = 0.0172). The lipid sources evaluated can be used in early lactation without negative effects being able to replace calcium salts of fatty acids in diets.


Introduction
The progress in management practices for dairy herds has provided better conditions for the animals expressing high yields.However, the increase in the individual milk production in most dairy herds in early lactation promote a negative energy balance period (BEN), even being offered high-energy diets.This fact is responsible for reducing the productive and reproductive performance in postpartum, increase the incidence of metabolic disorders and diseases in dairy cows (Wildman et al, 1982;Ruegg & Milton, 1995).
Bonded it, the growing concern of the population to consume animal products with reduced levels of saturated fatty acids makes research aimed at the nutrition of dairy cows to aim to reduce this content in dairy products.
Than, to minimize the effects of metabolic challenge and improve the quality of dairy products, fat sources have been used in animal feeding, to raise the energy density of diets without negative effects (Onetti & Grummer, 2004).There are numerous fat sources available into this purpose like free fat, particularly in the form of vegetable oils readily available to the rumen, or non-degradable rumen sources, which can be arti cially protected, mainly in the form of salts calcium fatty acids, or naturally protected sources, as the oilseeds (Jenkins, 1998;Naik, 2013).Worldwide, there are many commercial products presented like fatty acid calcium salts available for cattle nutrition, some individual characteristics, but all with high costs that can limit its use for dairy farms, by the high cost of diets when included.
The hypothesis was that it is possible to substitute calcium salts of fatty acids by whole oil seeds, assuming that the fat in the seeds is naturally protected by the integument of the shell and/or associated with the protein matrix and hence with slow release in rumen, generating no harmful effects on ruminal fermentation.The commercial protected fat replacement was tested by oilseed sun ower, linseed and soybean in the diet of lactating Jersey cows, and its effects on the intake and digestibility of nutrients, metabolic and productive parameters.

Animals and location
The experiment was from September to December, 2013, at the Empresa Brasileira de Pesquisa Agropecuária (Embrapa), research eld located in Southern Brazil (geographical coordinates 31º 52" S and 52º 29" W, altitude 13.24 m).The study was approved by following the norms of the Committee on Animal Research and Experimentation from Universidade Federal de Pelotas (case no.6850).
Eight 40 days milking multiparous Jersey cows, in 407 kg average weight and milk production of 20±2 kg between second and fourth lactation, were housed into a free stall and adapted to the experimental diets for 15 days before the start of the experiment.

Treatments and experimental diets
The treatments evaluated were calcium salts of fatty acids (CS) (Megalac-E ® ) and grain of Linseed (LI), Sun ower (SF) and Soybean (SY), to natural protection of lipids of the diet (Table 1) formulated to reach the same levels of energy, crude protein and neutral detergent ber (Table 2) tested in performance simulator, NRC (2001).The forage used was corn silage, provided twice daily and adjusted to 100 g/kg of orts.The concentrate was provided three times of day, individually, separated of forage, to ensure total intake.

Experimental managment
Each experimental period was conducted over 21 days, with a 17-day adaptation and a 4-day measurement period and cows were milked twice a day.Feed refusals were removed and weighed daily prior to delivery of the next meal.To estimate the fecal excretion was administered 10 g of chromium oxide (Cr2O 3 ) shared into two daily doses, after milking.The faeces samples were collected out in the morning and afternoon, during the four-day collection periods, with the individual samples stored in a freezer (-18 °C), forming a sampling-period per cow.Blood samples were taken at 15 th and 17 th days of each period, immediately after the morning milking, by jugular puncture.These were kept at rest for 10 minutes and was then centrifuged at 8000 rpm for 10 minutes, then placed in an isothermal box chilled and sent for analysis in a commercial laboratory.

Evaluations
Milk production was obtained by the average milk produced in the last four days for each period.Milk adjusted for energy was obtained by the equation described by Sjaunja et al. (1990).Milk analysis consisted in protein, fat, total solids, lactose and urea infrared spectroscopy according to AOAC 1996 (method 972.16), somatic cell count (SCC) by ow cytometry and the values processed according to the methodology described by Geroge and Shook (1993), in which somatic cell score (SCS) = [log2 (SCC/100)]+3.
The energy content of the diet was obtained from equations of NRC (2001) for digestible energy, metabolizable energy and net energy of lactation (NEL); the apparent digestibility was considered for energy calculations.The energy balance (EB) was estimated by NRC equations (2001).
Serum concentrations of glucose, total cholesterol and triglycerides were made by enzymatic colorimetric method, non-esteri ed fatty acids (NEFA) by enzymatic spectrophotometry, urea and the concentrations of the enzymes aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT) by kinetic enzymatic at a commercial laboratory.

Experimental design and statistical analysis
The experimental design was a double Latin square (4 x 4) with four treatments and four periods.Each animal was an experimental unit and the square was the repeated measure.It was used the SAS Glimmix procedure (SAS Institute Inc, 2013) followed the general linear mixed models methodology, with the choice of the distribution that would best t the data.This decision was made using the corrected Akaike value.The analysis of variance followed the mathematical model: Where: Y ijk is the observation concerning the i-th treatment (αi) in the j-th animal (aj) of the k-th period (p k ) in the l-th square (s l ).Treatments were considered as xed effect.The periods and the interaction treatments*periods as random effects.Data were submitted to analysis of variance and the treatment effect was evaluated by F test with 5% of error probability.When signi cant, means were compared by the Tukey-Kramer test (P = 0.05).

Apparent digestibility
The digestibility (Table 4) of DM, OM, and aNDF were not affected by treatments (P>0.05).The CP digestibility was lower for SY treatment (P=0.0014).Fat content digestibility was higher to CS treatment (P=0.0053).The NFC was superior for SW (P=0.0435) and lower in SW.
Production, milk composition and milk fatty acid pro le, feed e ciency and energy balance Milk yield (kg/d) was higher in CS in relation of SF and SY and the LI did not differ from the others (Table 5), however, milk yield corrected to energy (ECM), feed e ciency (FE) and energy balance were not affected by treatments (P>0.05).The milk composition (g/kg) as well as individual and total solids was not affected by treatments, except for lactose production that was higher in CS treatment compared to SY, but not of the LI and SF.

Biochemical blood pro le
The use of different lipid sources in diets did not affect (P>0.05)blood metabolic pro le of animals (Table 6).

Feed intake
There was no effect of treatment on DM, OM, CP, EE, aNDF and energy intake, because the diets were formulated to be similar in protein, energy and ber.When added fat in the form of calcium salts in the diet of lactating cows, depressive effects on consumption can be observed (NRC, 2001), and are associated with low palatability, unsaturation and chain length of acids fatty, as well as metabolic effects to the release of cholecystokinin (Allen, 2000).None of these possible effects was observed in our study.Results about nutrient intake are varied, but Kennelly (1996) suggested that fat addition in ruminants diets like whole oil seeds, proved to have less detrimental effect on dry matter intake, due to the slower release seed oil than the same amount, fed as free oil, resulting in no effect on dry matter intake.Petit et al. (2009) also observed that cows in early lactation fed with the highest level of linseed (150 g/kg of dry matter) did not reduce dry matter intake.
In studies with calcium salts of fatty acids, although there was a lower dry matter intake, Jenkins (1993) report that the energy intake did not fall because it increase in energy density or metabolic e ciency, without affecting milk production.Onetti & Grummer (2004) con rmed this hypothesis in a review at that the author compiled data from 41 trials that assessed supplementation from different sources and levels of fat to lactating cows.From 23 experiments evaluated, using calcium salts of fatty acids as the fat source, it observed a reduction in dry matter intake of 0.97 kg/d.However, when analyzing the milk production of 21 of these studies, the average milk production was increased by 1.29 kg/d.Thus, it is assumed that the net energy intake was maintained or increased with lipids supplementation.That is one of the main objectives of the use of fat in diets of lactating cows, to increase the energy density, particularly avoiding non-ber carbohydrates, in order to avoid acidosis risks in high producing animals.
The lack of effects on feed intake con rms our hypothesis, that oilseeds can be used as lipid sources to replace commercial protected fat, probably because they are processed at different parts of digestive tract.Besides that, there was no effect on net energy intake, that depends how and where the diet is metabolized.Probably, the slow release of oil in the rumen, leads to a partial protection, as suggested by Kennelly (1996).
The use of oil like whole grains, especially LI and SY provided a signi cant reduction in soybean meal use at diet, major proteic ingredient of livestock feeding, which has a high cost when compared to grain used.
The lower intake of NFC in SF and SY was not enough to reduce milk yield corrected to energy and milk solids production, therefore the diets were appropriate.

Apparent Digestibility
The absence of differences in DM, OM and aNDF ensures that lipid sources LI, SF and SY not causes negative effects on the digestive process.
Other results about digestibility of nutrients in dairy cows are quite heterogeneous.Martin  The main determinants of these effects are the amount of lipids and how they are fed (free oil or seed).In our study, these two factors contributed to the results and the few differences observed, since the inclusion of fat from LI sources, SF and SY occurred at an intermediate level, less than 35 g/kg of DM intake, maintaining low ruminal availability.
The digestibility of protein was less in SY.This is associated with a higher protein inclusion coming from soybean grain.In the other treatments was used soybean meal, with higher protein digestibility.Another associated factor may be related to reduced digestibility of soybean seed, occurring loss in feces.
The CS showed higher digestibility of EE, probably because that is composed of fat free saponi ed that solubilizes widely in the abomasum (Naik, 2013).Chouinard et al. (1998) observed an increase in digestibility of DM, CP, and aNDF in diets with AG calcium salts when compared to a control diet.In LI, SF and SY, the way the fat is arranged in the grains, there may be some limitations, due to the presence of brous exospermas in grain, or the association of that fat to protein grain matrix (Ekeren et al., 1992), that can affect negatively both the access of ruminal micro ora, as digestive enzymes in the small intestine.Supplementation with vegetable oil in free form (rich in unsaturated fatty acids) could be a trouble to ruminal fermentation, however when this is from oilseeds these disorders be reduced by slower fat release, without losses on nutrient digestibility (Coppock & Wilks, 1991), that seems to be con rmed in this study.
Production, milk composition and milk fatty acid pro le, feed e ciency and energy balance The higher milk production observed in CS may be related to the speci c characteristics of this diet, because although it was not found effects of treatments on the digestibility of OM, the higher digestibility of EE and the highest intake of NFC may be responsible for increased lactose production, that has high correlation (0.9742; r<0.0001) with milk production.However, it did not affect the energy corrected milk production and feed e ciency, that quali es all diets as effective to input high energy densities and should be considered the availability.The costs of different oil sources may be important to decision about which will be used.
The absence of changes in milk fat and protein reinforces the theory of natural protection in whole grains as well as the uniformity of the diets because these milk components are variable, both as a result of dietary lipids, or microbial growth, either for lack of fermentable carbohydrates or de ciency in protein intake.The lower production of lactose observed in SY treatment may be related to reduced intake of NFC, however, is not considered a limiting factor, because no effects were observed in the ECM nor in solids.
The milk urea nitrogen (MUN) was above to the standards (10 -16 mg/dL) proposed by Jonker et al. (1998) in LI and SF treatments, however, acceptable to the high protein levels of these diets (209 g/kg OM).So we can infer that the inclusion of lipids not depressed energy from NFC into rumen, with mean concentration of 368 g/kg OM.

Blood pro le
No effects on blood pro le (P>0.05)con rmed the similarity of diets and the potential of lipid sources.Blood glucose (62.1 mg/dL), triglycerides (3.34 mg/dL) and NEFA (0.30 mmol/L) are consistent with the physiological values described by Kaneko et al. (2008).
The concentration of blood urea was 39.3 mg/dL, within the range 15-42 mg/dL described by Wittwer (2000), but lower than those described by Kaneko et al. (2008), that accept values between 42.8 and 64.3 mg/dL.
Serum cholesterol, although not re ected treatment differences, was higher than 120 mg/dL, described by Kaneko et al. (2008).The increase occurred in response to intake of high levels of lipids (Wittwer, 2000).Elliott et al. (1993), showed that the elevated cholesterol levels in diets with oil may be related to greater need to transportation of long chain fatty acids.
The NEFA means were 0.30 mmol/L (Table 6), that combined with energy balance data (Table 5) show that no BEN during the trial, due the effectiveness of the diets.The absence of effects on AST and GGT concentrations con rms that did not liver damage by the fat sources used.
It was observed that higher levels of CLA cis 9 trans 11 for CS, however, in the same way, also found, despite low, values of CLA cis 12 trans 10, its isomerized form.Several factors in uence biohydrogenation in the rumen and can change the amount and composition of unsaturated fatty acids, both those destined for deposition in adipose tissue and those secreted in milk.Biohydrogenation can happen completely or with the formation of intermediate products, such as C18: 2c9t11, these compounds being absorbed in the ruminal walls and, in blood ow, can be absorbed by the mammary gland and incorporated into milk.Into the bloodstream, they can be absorbed by the mammary gland and incorporated into milk.However, when we observed the MUFA values, SY presented higher values than the other treatments.Unlike the other diets evaluated, where MUFA content was around 20% of the total fatty acids, SY presented values of 83.52%.This high content of MUFA in the composition of SY and its higher values in the nal composition of milk compared to other diets evaluated, demonstrates that for total e ciency of biohydrogenation, a balance is needed between the fatty acid compounds present in the feed.

Conclusion
The replacement of fatty acid calcium salts for oilseeds such as soybeans, sun ower and linseed is possible within the levels used in this study, without negative effects on the production or animal health.The decision about the use these sources should re ect the market prices and availability.Sun ower showed higher levels of monounsaturated fatty acids in the nal composition of the milk.Higher levels of CLA cis 9 trans 11 in milk were found when supplied with fatty acid calcium salts.

Table 7 .
Effect of treatments on milk fatty acid pro le1